The Mars Apparition of 2021-2023
by Martin J. Powell
The path of Mars against the background stars from July 2022 to May 2023, shown at 10-day intervals (click on the thumbnail for the full-size image, 199 KB). During this apparition Mars describes a 'hybrid' shaped path against the stars (half loop, half 'zig-zag'), in contrast to the zig-zag that it described during the planet's previous apparition in 2019-21. The path of Uranus is also shown for reference (a detailed finder chart for this planet for the current year can be found on the Uranus page). Jupiter enters the chart coverage at a later stage in Mars' apparition. A planetary conjunction between Mars and Uranus takes place on August 1st 2022 (marked on the chart by the symbol ). For more details on this and five other conjunctions of Mars involving other planets, see the planetary conjunctions section below.
The star map applies to observers in the Northern hemisphere (i.e. North is up); for the Southern hemisphere view, click here (203 KB). The faintest stars shown on the map have an apparent magnitude of about +4.8. Printer-friendly versions of this chart are available for Northern (92 KB) and Southern hemisphere (94 KB) views. Astronomical co-ordinates of Right Ascension (longitude, measured Eastwards in hrs:mins from the First Point of Aries) and Declination (latitude, measured in degrees North or South of the celestial equator) are marked around the border of the chart. Click here (160 KB) to see a 'clean' star map of the area (i.e. without planet paths); observers may wish to use the 'clean' star map as an aid to plotting the planet's position on a specific night - in which case, a printable version can be found here (79 KB). Photographs of this region of the night sky can be seen below.
The five star names shown in yellow-green were officially adopted by the International Astronomical Union (IAU) in 2017.
At superior conjunction on October 8th 2021 (when it passes directly behind the Sun in the constellation of Virgo, the Maiden), Mars is positioned 2.6286 Astronomical Units (AU) from Earth (393.2 million kms or 244.3 million miles). Were it to be visible from Earth at this time, its apparent magnitude would be +1.6 and its apparent size only 3".5 (i.e. 3.5 arcseconds, where 1" = 1/60th of an arcminute or 1/3600 of a degree). Mars becomes visible in the dawn twilight from around the third week of November (Northern Tropical and Equatorial latitudes), from late November/early December (mid-Northern latitudes) and from early/mid-December (Southern Tropical and mid-Southern latitudes). Last to see the planet emerge are far Southern latitudes (from late December at 45° South) and high Northern latitudes (from early July 2022 at 60° North). At the start of the apparition, Mars appears over the ESE horizon at dawn from most latitudes except the higher Northern hemisphere, from where it appears towards the South-east (at 50° North) and the East (at 60° North).
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Mars enters the constellation of Libra, the Balance, on November 11th. As the planet reaches a solar elongation (angular distance from the Sun) of 15° West on November 23rd, the planet is rising in twilight in the ESE between 55 minutes (15° South) and 1¼ hours (40° North) before sunrise. The Red Planet is slowly pulling away from the Sun at a rate of just 0°.3 per day at this time.
On December 1st Mars passes 8º.5 South of the star Zubeneschamali ( Lib or Beta Librae, mag. +2.5), the Northernmost star of the quadrilateral figure. It is said to have a greenish hue when viewed with optical aid - one of the very few stars in the night sky which appears this colour.
Olympus Mons (Mount Olympus), the largest volcano in the Solar System, appears as a small circular patch of light at the lower left of the Martian disk in this image by Manolo Rodriguez (Seville, Spain) taken at the planet's opposition in October 2020 (click on the thumbnail for a larger image, 6 KB). Rodriguez used a 280mm (11-inch) Schmidt-Cassegrain reflector telescope fitted with a CMOS camera (Image: Manolo Rodriguez / ALPO-Japan).
On December 3rd Mars is involved in a lunar occultation, one of several such events which take place during the planet's 2021-23 apparition. A lunar occultation occurs when the Moon passes in front of a planet, blocking it from view for a short period of time. Because of the rotating Earth, the relative closeness of the Moon to the Earth and the consequent effect of parallax, any given lunar occultation can only be observed from a particular region of the world. The December 3rd occultation starts from around 23 hours UT on December 2nd and is visible in twilight from Mongolia and North-eastern China. For a map and timings of this event, follow the link provided in the Moon near Mars section below.
The 2021-23 apparition truly gets underway as Mars reaches a solar elongation of 20° West on December 8th. At this early stage in the apparition, Mars appears as a feeble, pale-orange 'star', shining around one half-maginitude fainter than the star Spica ( Vir or Alpha Virginis, mag. +1.0) in Virgo, some 32° to the West of the planet. Mars barely gains any significant altitude before disappearing into the brightening dawn twilight. Telescopically it is a disappointing sight, its tiny apparent size frustrating most attempts to obtain a clear view of the planet's surface.
Also on December 8th, Mars passes 4°.4 South of the star Zubenelhakrabi ( Lib or Gamma Librae, mag. +3.9), the Easternmost star of Libra's quadrilateral figure. Before IAU standardisation in 2017 (of which, see below) the name was alternatively spelled Zuben Elakrab. On December 14th the planet passes 3°.4 South of the star Lib (Theta Librae, mag. +4.1), positioned near the Eastern border of Libra.
Mars enters Scorpius, the Scorpion, on December 15th. On December 16th the Red Planet passes 5º.6 North of the star Fang ( Sco or Pi Scorpii, mag. +2.8), at the front end of the Scorpion. It is named after the fourth lunar mansion in ancient Chinese astronomy. In ancient China the four stars that we now consider to form the head of the Scorpion (1 Sco, Sco, Sco and Sco) were known as Fáng (‘Room’), the name of Sco in particular (Fáng Xiù) translating as "the First Star of Room". The name was formerly adopted in 2017 by the Working Group on Star Names (WGSN), a newly-established division of the IAU which since 2016 has been cataloguing and standardizing the star names used by the international astronomical community. In order to accommodate a wider diversity of global culture, the WGSN has adopted some names from mythologies other than Arab, Greek and Roman, whose star names dominate the night sky. Mars passes several other 'newly-named' stars during its 2021-23 apparition, many of which will be discussed below, along with a number of better-known star names (proper names) for which the IAU have now introduced standardized spellings.
Later on the 16th, Mars passes 2º.0 North of the star Dschubba ( Sco or Delta Scorpii, mag. +2.3), an Arabic name meaning 'forehead'. The star unexpectedly brightened in the year 2000 as it ejected a shell of gas, though it has long since faded.
Mars passes 1º.0 South of the double star Acrab (1 Sco or Beta-1 Scorpii, combined mag. +3.9), formerly known as Graffias, on December 18th. Its two blue-white components (1 Sco and 2 Sco) are magnitudes +2.6 and +4.9, separated by 13".7 and easily seen in small telescopes. Beta-1 Scorpii is itself also double, having a tenth-magnitude companion positioned less than an arcsecond away, separable only in larger telescopes.
Table showing the position and apparent magnitude of Mars for the early part of the 2021-23 apparition (click on the thumbnail for the full-size table, 27 KB). The magnitudes, diameters and solar elongations listed here refer to the middle of the period in question. In this and the tables which follow, the rising and setting directions of the constellations listed can be found by referring to the zodiacal constellation rise-set direction table.
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On December 19th Mars crosses to the South of the ecliptic, the path along which the Sun, the Moon and planets follow closely. From 03 hours UT that day the planet passes a short distance North of the two Omegan stars Jabhat al Akrab (1 Sco or Omega-1 Scorpii, mag. +3.9) and 2 Sco (Omega-2 Scorpii, mag. +4.3). The stars are separated in the night sky by 0º.24 and, together with the stars Jabbah ( Sco or Nu Scorpii, mag. +4.0) to their North-east, Acrab to their NNW and Dschubba to their South-west, they form an eye-catching asterism (star pattern) in the Northern region of the Scorpion. Mars' passage of the Omegan stars takes a little under five hours, the planet passing 13' (0º.21) South of 1 Sco at 0310 UT and only 2'.7 (0º.04) South of 2 Sco at 0804 UT. Mars passes 1º.6 South of the aforementioned Jabbah, a multiple star with brighter components of magnitude +4.0 and +6.3, on December 20th.
At around 1424 UT on December 22nd Mars passes 1º.6 North of the eighth-magnitude globular cluster Messier 80 or M80 (NGC 6093) which, like most of the brighter globulars, appears as a faint, circular, fuzzy spot of light through binoculars under dark skies. On December 24th Mars enters the constellation of Ophiuchus, the Serpent-Bearer or Serpent Holder, passing 4º.1 North of the variable star named Alniyat ( Sco or Sigma Scorpii, mag. +2.9v), positioned at the 'heart' of the Scorpion, later that same day.
On December 26th Mars passes 4º.6 North of the Scorpion's brightest star Antares ( Sco or Alpha Scorpii, mag. +1.0v), a red supergiant which is at least 400 times the size of our Sun! The star twinkles (scintillates) with a distinct orange-red hue, rivalling the colour of the Red Planet. Indeed, the name Antares derives from the ancient Greek 'anti Ares' meaning 'rival of Mars' (Ares being the ancient Greek god of War). On this occasion Mars is about one half-magnitude fainter than its stellar counterpart.
From late December, observers at latitudes in the vicinity of 45º South begin to see Mars emerge into the dawn sky, low over the ESE horizon.
Over the following two weeks Mars passes North of five stars which were formally assigned 'new' names by the IAU in 2017 and 2018. Four of them are located in the tail of Scorpius and one - the faintest of the five - is in Southern Ophiuchus. On December 28th Mars passes 6º.1 North of the star Paikauhale ( Sco or Tau Scorpii, mag. +2.8), which is a Hawaii'an name for a vagabond.
From around 19 hours UT on December 31st Mars is involved in the second lunar occultation of the planet's apparition, when the waning crescent Moon occults the Red Planet. The event is visible in twilight/darkness from Southern Australia (South Australia, Victoria and Tasmania). For a map and timings of this event, follow the link provided in the Moon near Mars section below.
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On January 2nd Mars passes three of the newly-named stars: 11º.8 North of Larawag ( Sco or Epsilon Scorpii, mag. +2.2) at around 1645 UT and, at around 2345 UT, 15º North of Xamidimura (1 Sco or Mu-1 Scorpii, mag. +2.9) and, only moments later, Pipirima (2 Sco or Mu-2 Scorpii, mag. +3.5). Larawag is positioned about half-way along the Scorpion's tail and is an Aboriginal name derived from the Wardaman culture of Northern Australia; it means 'signal watcher'. Xamidimura and Pipirima are located 3º.5 South of Larawag, also in the Scorpion's tail. The two stars are separated in the night sky by just 5'.7 (0º.1), making them appear as a double star, however this is a line-of-sight effect and they are not physically related. Xamidimura is an eclipsing binary of the Beta Lyrae variable star type whilst Pipirima is a blue-white subgiant star. Xamidimura is the historical name given to the star by the Khoikhoi people of South Africa; it means 'eyes of the lion'. The name Pipirima comes from Polynesian mythology. It refers to a Tahitian story of two inseparable twins (Pipirima and Réhua) who fled from their parents and became stars in the night sky.
On January 9th Mars passes 7º.4 South of the star Sabik ( Oph or Eta Ophiuchi, mag. +2.5), the second brightest star in Ophiuchus. The name is Arabic and translates as 'the preceding one'.
On January 10th Mars reaches magnitude +1.5, making it a first magnitude object. Also on the 10th the Red Planet passes 3º.3 North of the star Guniibuu (36 Oph A or 36 Ophiuchi A, mag. +5.1), another star assigned a 'new' name by the IAU in this region of the night sky. It is an Australian Aboriginal name meaning a robin red-breast, derived from Euahlayi-Kamilaroi culture. Guniibuu is one component of a pair of orange dwarf stars (A and B) which are easily split in small telescopes.
Six stars in Scorpius were formally assigned new names by the International Astronomical Union in 2017 and 2018 (click on the thumbnail for the full-size image, 41 KB). In this map of the constellation they are labelled in dark yellow.
On January 12th Mars passes 1º.6 North of Ophiuchus' Southernmost bright star Oph (Theta Ophiuchi, mag. +3.2). On older star maps the stars Oph and Guniibuu were depicted as marking the ankle of the Serpent-Bearer.
Around mid-month, brilliant white Venus (magnitude -4.1) emerges into the dawn sky to the ENE of Mars, at the start of its 2022 morning apparition. At the present time it is skirting the Northern border of neighbouring Sagittarius, the Archer. The planet is positioned 24º to the ENE of Mars at midnight UT on the 14th, 18º.5 to the ENE of it on the 19th and 14º to the ENE of it on the 24th.
To the South of Ophiuchus the Scorpion's tail curves around to the East and North-east, deep within an area rich in Milky Way galaxy stars. Mars passes 13º.9 North of the star Lesath ( Sco or Upsilon Scorpii, mag. +2.6) on January 15th and 13°.6 North of the star Shaula ( Sco or Lambda Scorpii, mag. +1.6) on the 16th. Together these two stars form the 'sting' at the end of the Scorpion's tail.
On January 17th Mars passes 8º.1 South of the star Ser (Xi Serpentis, mag. +3.5), positioned 6º.5 to the East of the aforementioned Ophiuchan star Sabik and at the South-eastern corner of a trapezoidal arrangement of third and fourth-magnitude stars. Located in the constellation of Serpens Cauda, the Serpent's Tail, the other two stars are Ser (Omicron Serpentis, mag. +4.2) at the North-eastern corner of the trapezoid and Ser (Nu Serpentis, mag. +4.3) at the North-western corner. This is, of course, the tail section of the serpent, of which the Serpent-Bearer (namely, the Greek god Asciepius or Aesculapius) is holding. Mars leaves Ophiuchus and enters Sagittarius on January 19th, passing 4º.1 North of the star 3 Sgr (3 Sagitarii, mag. +4.6) on the 20th.
On January 21st Mars passes 13º.3 North of another star in Scorpius' tail to be assigned a 'new' formal name by the IAU - in this case, in the year 2017. Fuyue (G Scorpii, mag. +3.2) is positioned at the tail-end of the Scorpion. Fu Yue was a Chinese labourer who became a wise minister and a chancellor of the Emperor Wu Ding (ca. 1250-1192 BC) of the Shang dynasty. After Fu Yue's death he is said to have become part of a constellation known as The Sieve, situated in the Tail mansion (Wei Xiù) in ancient Chinese astronomy.
Over the course of 30 hours between January 25th and 26th, Mars passes 27' (0º.45) to the North of the gaseous nebula M8 (NGC 6523), commonly known as the Lagoon Nebula. With apparent dimensions of 90' by 40' and an integrated magnitude (i.e. its apparent magnitude if the cluster were concentrated into a single point) of about +5 it is visible to the naked eye as a hazy patch of light under truly dark skies. Telescopes reveal a dark lane through its centre and a star cluster (NGC 6530) in the Eastern half of the nebula, comprising around two dozen stars of 7th magnitude and fainter. The Red Planet begins its passage of M8 from around 15 hours UT on the 25th and ends it at around 21 hours UT on the 26th.
Positioned a short distance to the NNW of M8 is another gaseous nebula - M20 or NGC 6514 - also known as the Trifid Nebula. Its brightest region is roughly elliptical in shape and measures 29' by 27'. Seen through telescopes under dark skies, three dark dust lanes can be seen, from which the nebula gets its name. At the centre of the nebula is a double star comprising components of 7th and 8th magnitude. Mars passes 51' (0º.85) to the South of M20 over the course of seven hours from 16 hours UT to 23 hours UT on the same day. The Red Planet is positioned roughly mid-way between M20 and M8 at around 0120 UT on the 26th.
Over the next few weeks, Mars passes to the North of the so-called Teapot asterism in South-western Sagittarius. Seen in a North-up orientation, the stellar teapot appears 'tipped up', pouring its contents South-westwards into neighbouring Scorpius. The Teapot extends from the star Alnasl ( Sgr or Gamma Sagittarii, mag. +3.0) in the West to the star Tau Sagittarii ( Sgr, mag. +3.3) in the East. The planet's passage of this asterism starts at around 20 hours UT on January 26th when Mars passes 6º.6 North of Alnasl, at the front of the Archer's bow (also the spout of the teapot). Prior to IAU standardisation in 2016 the star was commonly known as Nash.
On January 27th Mars attains its most Southerly declination for this apparition, at -23° 51' 23" (-23°.85646 in decimal format) in Western Sagittarius. Across the inhabited world the planet now rises at its most Southerly point on the local horizon; in the ESE from all except higher Northern and Southern latitudes, from where it rises in the South-east. The planet's high-Southern declination significantly affects the duration which it spends above the horizon at any given latitude: rising 1½ hours ahead of the Sun at 60º North (from where it is still rising in twilight), two hours before the Sun at 40º North, 2½ hours before sunrise at the Equator and 2¾ hours before sunrise at 35º South. Before disappearing from view in the brightening dawn sky, Mars attains an altitude of just 7° at latitude 50° North, 13° at 40° North, 28° at the Equator and 26° at 35° South.
On January 29th Mars passes 2º.7 South the star Polis ( Sgr or Mu Sagittarii, mag. +3.8v), positioned just to the North-west of the Teapot. It is an eclipsing binary star with a tiny brightness variation of ±0.1 magnitudes. Although not part of the Teapot, it is sometimes considered to be included in an older asterism called the Milk Dipper, which is envisaged as a ladle dipping into the rich Milky Way. Venus, now some 10º.7 to the North-east of Mars, reaches its Western stationary point on the same day, positioned on the Northern border of Sagittarius with Scutum, the Shield.
At the end of the month the planet Mercury (mag. +1.7), in North-eastern Sagittarius, emerges into the dawn sky at the start of its first morning apparition of 2022. This particular apparition favours Southern hemisphere observers, the ecliptic forming a steep angle to the Eastern horizon at dawn at this time of year. Over the next fortnight Mars, Venus and Mercury will appear as a triangle in the Archer, the latter planet pulling away from the pair and stretching the triangle Eastwards from around mid-February.
Mars passes 6º.0 North of the star Kaus Media ( Sgr or Delta Sagittarii, mag. +2.7), positioned at the centre of the Archer's bow, on January 31st. Before IAU standardisation in 2016 it was also known by the names Kaus Meridionalis and Kaus Medius. On February 1st the planet passes 10º.7 North of Sagittarius' brightest star Kaus Australis ( Sgr or Epsilon Sagittarii, mag. +1.8), positioned at (or near) the Southern tip of the Archer's bow. On February 2nd the planet passes 1º.6 North of the star Kaus Borealis ( Sgr or Lambda Sagittarii, mag. +2.8) which marks the top of the Teapot asterism. The name Kaus is Arabic for 'bow', its Northern and Southern sections (Borealis and Australis) being later Latin additions.
Mercury, having brightened one whole magnitude to +0.7 since its first dawn appearance, reaches its Western stationary point on February 4th, positioned 17º to the ENE of Mars and 13º.3 to the East of Venus.
At 9 hours UT on February 5th Mars passes 11' (0º.18) North of the relatively bright globular cluster M22 (NGC 6656) which is considered to be one of the finest globulars in the night sky. Its integrated magnitude is about +5.9 and it has an apparent diameter of 24'. It is just visible to the naked-eye from dark sites, is easily seen through binoculars and is a spectacular sight through telescopes.
Mars passes 3°.4 North of Sgr (Phi Sagittarii, mag. +3.1) on February 8th, 0°.7 South of Ainalrami (1 Sgr or Nu-1 Sagittarii, mag. +4.8), in the Archer's head, on the 10th and 2°.8 North of the constellation's second-brightest star Nunki ( Sgr or Sigma Sagittarii, mag. +2.0) on the 11th. Mars, Venus and Mercury (mag. +0.2) form their closest triangular grouping on February 12th, with Mercury at the apex, located 14°.1 to the East of Mars and Venus 6°.6 to the North of Mars. The triangle points East towards the neighbouring constellation of Capricornus, the Sea-Goat. Mars passes 6°.6 North of Ascella ( Sgr or Zeta Sagittarii, mag. +2.6), at the base of the Teapot's handle, on the 13th.
At 0211 UT on February 14th Mars and Venus meet in the first of six planetary conjunctions which take place during the planet's 2021-23 apparition. A planetary conjunction occurs whenever any two planets attain the same celestial longitude, such that they appear close together in the night sky. In this instance the pair are separated by a sizeable apparent distance of 6°.5 - so wide that many might not consider it a true conjunction as such. The conjunction is well placed for Southern hemisphere observers but poorly placed for those at higher Northern latitudes. Over the next 5½ months Mars will pass four other Solar System planets during the course of its circuit through the zodiac. For more details, refer to the planetary conjunctions section below.
At 05 hours UT on the same day (14th) Mars passes 1°.5 South of Sgr (Omicron Sagittarii, mag. +3.7), one of three stars marking the Archer's head. Seventeen hours later, at 22 hours UT, the planet passes 4º.5 North of Sgr (Tau Sagittarii, mag. +3.3), the last of the four bright stars which form the Teapot's handle.
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Having left the bulk of the brighter stars of Sagittarius behind it, Mars continues on its Eastward course, passing 2°.1 South of Albaldah ( Sgr or Pi Sagittarii, mag. +2.9), also in the Archer's head, on February 15th. It is a multiple star whose Arabic name apparently means 'the town'. Mercury (mag. +0.1) enters Capricornus on the same day, positioned 14°.4 East of Mars. Mercury attains its greatest elongation West of the Sun (26°) on February 16th; from around this time it begins to pull away from Mars and Venus, elongating the planetary triangle Eastwards as it heads back towards the Sun. It is 14°.6 East of Mars at midnight UT on the 16th, 15°.6 East of the Red Planet on the 19th and 16°.7 East of it on the 22nd.
The North-eastern region of Sagittarius, which Mars now occupies, has numerous stars of 4th magnitude or fainter. Amongst them is the star 52 Sgr (52 Sagittarii, mag. +4.6), which on older star maps is shown positioned at the 'rump' of the centaur figure. Mars passes 2°.5 to the North of 52 Sgr at on February 24th.
Around this time, the planet Saturn (mag. +0.7) begins to emerge into the dawn sky, positioned some 27° to the East of Mars in central Capricornus. Saturn is at the start of its 2022-23 apparition, which will see it reach its peak brightness (+0.3) at opposition in early August. The arrival of the ringed planet in the dawn sky creates a quartet of planets across 28° of sky. The waning crescent Moon passes by the quartet from February 27th to March 2nd.
Mercury, now magnitude +0.0, is racing Eastwards towards Saturn at a rate of 1°.2 per day. It is 8°.2 to the WSW of Saturn at midnight UT on February 24th, 4°.7 to the WSW of it on the 27th and 1°.1 to the South-west of it on March 2nd. Later on March 2nd the two planets pass each other in conjunction, positioned 23° to the WSW of the Sun and 21°.7 to the ENE of Mars. Mercury then heads into the twilight and becomes lost from view from around mid-March.
Located at the central Eastern end of Sagittarius are a group of four 4th-magnitude stars, within 2° of each other, named the Terebellum. The name is a Latin translation of an original Greek word meaning 'four-sided figure', allotted to this star group by Claudius Ptolemy (ca. 100-170 AD) in his famous star catalogue, the Almagest. The Terebellum comprise the stars Sgr (Omega Sagittarii, mag. +4.7), 59 Sgr (mag. +4.7), 62 Sgr (mag. +4.5) and 60 Sgr (mag. +4.8). Mars passes between 4°.7 and 6°.4 North of the group between March 2nd and 4th.
With Mercury's departure from the morning sky, Mars now forms a triangle with Venus and Saturn, the latter planet being positioned at the apex, the triangle pointing East towards neighbouring Aquarius, the Water-Carrier. The triangle will continue to be visible through to late March.
Mars enters Capricornus on March 5th, followed by Venus two days later, positioned 4°.4 to the NNW of the Red Planet. Since their conjunction in mid-February the two planets have been moving Eastwards along the ecliptic more or less in unison, the angular distance between them closing very slowly.
On March 9th Mars passes 8º.0 South of the star Algedi (2 Cap or Alpha-2 Capricorni), an apparent naked-eye double star with Prima Giedi (1 Cap or Alpha-1 Capricorni, mag. +4.2). Prior to IAU standardisation in 2016 Algedi was also known by the name Secunda Giedi. The stars are not physically related, since they lie at very different distances from the Earth; the closeness of the two stars is therefore a line-of-sight effect.
Mars, Venus and Algedi line up along 7º.9 at around 7 hours UT on March 10th, Venus being positioned very nearly at the centre of the line. Mars passes 5º.7 South of another double star, Dabih (1 Cap or Beta-1 Capricorni, mag. +3.1), on the same day. It is a yellow star with a blue companion of magnitude +6.1, positioned 3'.5 to the West, visible in binoculars and small telescopes. Mars, Venus and Dabih line up along 5º.6 at around 21 hours UT.
Mars and Venus reach conjunction at 1411 UT on March 12th, Venus being 4º to the North of the Red Planet. Much like the conjunction between these two planets a month earlier, the event is best seen from the Southern hemisphere. After conjunction, Venus slowly pulls ahead of Mars to the East, being 3º.9 to the NNE of Mars at midnight UT on March 16th, 3º.9 to the North-east of it on the 19th and 4º.2 to the North-east of it on the 22nd.
Venus attains its greatest elongation from the Sun (46º West) on March 20th. Around this time, the giant planet Jupiter (mag. -1.9) begins to appear in the dawn sky at the start of its 2022-23 apparition. As it emerges it is about 38º to the ENE of Mars, positioned in North-eastern Aquarius. Venus temporarily enters Aquarius through its South-western border on March 23rd, positioned 4º.3 to the North-east of Mars.
At around 18 hours UT on March 24th Mars, Venus and Saturn form an isoscelene triangle, with Venus at the North-pointing apex. The long side (Mars-Saturn) is 7º.5 in length and the other two sides (Mars-Venus and Venus-Saturn) are 4º.5 long; Venus is in Aquarius and the other two are in Capricornus. At 22 hours UT on the same day Mars passes 34' (0º.56) South of Cap (Theta Capricorni, mag. +4.0), which is positioned at the centre of the Sea-Goat.
On March 27th Venus returns to Capricornus, entering its North-eastern region, positioned 5º to the North-east of Mars and 2º.7 to the North-west of Saturn. At about 18 hours UT on March 28th Mars, Saturn and Venus form a right-angled triangle, with Saturn at the right-angle. The angular distance from Mars to Saturn is 4º.9, from Saturn to Venus is 2º.1 and from Mars to Venus (hypotenuse) is 5º.4. The waning crescent Moon passes by the trio between March 28th and the 31st. On March 29th Venus and Saturn are in conjunction in North-eastern Capricornus, positioned 4º.8 to the North-east of Mars. On March 30th Mars passes 11' (0°.18) North of the star Cap (Iota Capricorni, mag. +4.2), which is positioned at the 'rump' of the Sea-Goat figure.
As April begins, Mars is approaching Saturn at a rate of about 0°.7 per day. The Red Planet is 2°.7 to the WSW of Saturn at midnight UT on the 1st, 2° to the WSW of it on the 2nd and 1°.3 to the South-west of it on the 3rd.
Located several degrees to the North of Mars at this time is the Western half of Aquarius. Its brightest star is Sadalsuud ( Aqr or Beta Aquarii, mag. +2.9), a name which is Arabic for 'the lucky one of the lucky', its meaning having astrological origins. Mars passes 10º.2 South of Sadalsuud on April 2nd.
In early April the most distant 'true' planet Neptune (mag. +7.9) begins to appear in the dawn sky. Requiring binoculars or a telescope to be seen, it is located very close to the North-eastern boundary of Aquarius with Pisces, the Fishes. At midnight UT on April 3rd Neptune is 1º.9 ESE of Jupiter.
Positioned some 2º.7 to the South-east of the aforementioned star Sadalsuud in Aquarius is the binary star Bunda ( Aqr or Xi Aquarii, mag. +4.7), a name formally assigned by the IAU in 2018 after a Persian lunar mansion. Mars passes 7º.5 South of Bunda at around 12 hours UT on April 4th.
At 2204 UT on the same day (4th), Mars finally catches up with Saturn, passing 0º.3 to the South of the ringed planet in the third planetary conjunction of the apparition. The conjunction is ideally placed for Southern hemisphere observers. Saturn's rings are still nicely presented to the Earth, although they are slowly closing; they will be seen edge-on to the Earth in 2025. At this time Saturn's globe, whose North pole is tilted in our direction, appears about 16" across whilst the rings are about 36" across. By comparison, the Martian disk appears just 5".2 across, one-third the size of Saturn's globe. At the moment of conjunction, Venus is located 7º to the ENE of the pair, having now re-entered Aquarius.
Mars passes 1°.4 North of Nashira ( Cap or Gamma Capricorni, mag. +3.7) on April 5th and 1°.4 North of Deneb Algedi ( Cap or Delta Capricorni, mag. +2.9), the brightest star in the constellation, on the 7th. Deneb Algedi is Arabic for 'tail of the goat' and it was also known as Deneb Algiedi or Scheddi before IAU standardisation in 2017.
Mars leaves Saturn behind it, being 41' (0°.68) to the East of the ringed planet at midnight UT on April 6th, 1°.3 East of it on the 7th and 2° East of it on the 8th.
The Red Planet enters Aquarius at around 14 hours UT on April 11th, at which time Venus is located 9º.2 to the ENE and Saturn is 4º.4 to the WSW. Mars passes 12º.8 South of the constellation's second-brightest star Sadalmelik ( Aqr or Alpha Aquarii, mag. +2.9) at 21 hours UT on April 13th, then 47' (0°.78) North of the star Aqr (Iota Aquarii, mag. +4.2), at the 'knee-joint' or 'hip' of the Water Carrier (depending upon the star map depiction) at 0430 UT on April 14th. Mars passes 4º.3 South of the star Ancha ( Aqr or Theta Aquarii, mag. +4.1), in central Aquarius, on April 17th.
Since their triangular formation in late March Venus has been rapidly pulling away Eastwards from Mars and approaching Jupiter at a rate of about 0°.9 per day. At around 9 hours UT on April 18th Venus is positioned mid-way between Mars and Jupiter, the Mars-Venus and Venus-Jupiter distances being 11º.4. Saturn is 9º.6 to the WSW of Mars.
From April 19th to the 24th Mars is positioned about 11º South of Aquarius' best-known naked-eye feature, the so-called 'Steering Wheel' asterism. On older star maps it marked the amphora from which the Waterman poured his water, though on more recent star maps it sometimes appears as the Waterman's head. At the centre of the 'wheel' is the star Aqr (Zeta Aquarii, mag. +3.7) with the stars Sadachbia ( Aqr or Gamma Aquarii, mag. +3.9), Aqr (Eta Aquarii, mag. +4.0) and Aqr (Pi Aquarii, mag. +4.8) encircling it. It is one of several asterisms in the zodiac with which beginner astronomers should become familiar. Mars passes 10º.2 South of Sadachbia on April 19th and 10º.9 South of Aqr on April 21st. Mars passes just 14' (0º.23) South of the star Aqr (Sigma Aquarii, mag. +4.8), at the approximate centre of the constellation, at 1305 UT on April 22nd. The planet passes 10º.2 South of Aqr - at the Eastern edge of the 'wheel' - on April 24th.
At around 16 hours UT on April 25th Mars is positioned mid-way between Venus and Saturn, the angular distance between the latter two planets being 28º.2. Jupiter is 4º.7 to the ENE of Venus, the four planets now forming a line some 33º in length from South-western Pisces through to North-eastern Capricornus. All four planets are positioned about 1º South of the ecliptic. Neptune is also in the line, positioned roughly mid-way between Venus and Jupiter. The waning crescent Moon passes the line-up from April 25th to 28th.
Mars passes 4º.5 North of the star 2 Aqr (Tau-2 Aquarii, mag. +4.0) on April 29th and 1º.2 South of the star Aqr (Lambda Aquarii, mag. +5.8) on April 30th.
Jupiter and Venus are in a close conjunction on April 30th in South-western Pisces, when they come to within just 0º.2 of each other. Mars is positioned 16º to their South-west whilst Neptune is 3º.3 to their WSW. The conjunction is best seen from the Southern hemisphere.
On May 1st Mars passes 7º.3 North of the star Skat ( Aqr or Delta Aquarii, mag. +3.2) which on old star maps marked the Waterman's lower right leg. The following day, Neptune moves from Pisces into Aquarius, ending a continuous 11-year period spent by that planet in the Fishes.
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Far to the South of Mars in May is the constellation of Piscis Austrinus, the Southern Fish. Ancient Greek and Babylonian mythology describes it as being the parent of the much more famous zodiacal Pisces and it was envisaged as drinking the water poured from the Waterman's amphora. The constellation's brightest star is Fomalhaut ( PsA or Alpha Piscis Austrini, mag. +1.2), a blue-white star whose Arabic name translates as the 'fish's mouth'. With a declination of -29º.6 it cannot be seen North of latitude 60º.4 North. Even at mid-Northern latitudes the star's altitude at meridian transit is low, reaching just 10º above the Southern horizon at 50º North and 20º above the horizon at 40º North. From the Northern hemisphere the star shines in splendid isolation, being the brightest star for some distance around it. Mars passes 21º.7 North of Fomalhaut on May 2nd but the star is a prominent object to the South of the Red Planet throughout its passage of Aquarius.
At 2210 UT on May 7th Mars passes 34' (0°.56) South of the star Aqr (Phi Aquarii, mag. +4.2), which on older star maps is one of several stars which marked the stream of water which flowed from the Waterman's amphora; more recent maps have shown it marking the top of his amphora. The following day at 12 hours UT the planet passes 2°.6 North of the star 1 Aqr (Psi-1 Aquarii), also magnitude +4.2, another star in the water stream. Mars is positioned precisely between Aqr and 1 Aqr at around midnight UT on May 8th.
On May 8th Venus enters the constellation of Cetus, the Whale. Five planets are now spread in a line 42° long; in order of angular distance from the Sun, they are: Venus, Jupiter, Neptune, Mars and Saturn. Venus is now pulling away from the group towards the ENE at a rate of about 1° per day.
Between May 8th and 19th, Mars is positioned several degrees South of the Circlet of Pisces, which is located at the Western end of Pisces, the Fishes. The Circlet comprises six stars of fourth and fifth magnitude, although under light-polluted skies it is likely that some or all of them will not be seen with the naked-eye. The passage begins at 2230 UT on May 8th when the planet passes 9°.5 South of Aqr (Gamma Piscium, mag. +3.7), the Westernmost star of the Circlet.
On May 9th Mars passes two more stars in the water stream: 2°.9 North of 2 Aqr (Psi-2 Aquarii, mag. +4.2) at 4 hours UT and 3°.5 North of 3 Aqr (Psi-3 Aquarii, mag. +5.0) at 14 hours UT. At 1730 on the same day, the planet passes 58' (0°.96) South of the star 96 Aqr (96 Aquarii, mag. +5.7), a double star with a magnitude +10.4 companion located 10" distant. Mars will occult this star in the evening sky in January 2032.
At around 1330 UT on May 11th Mars, Jupiter and Venus are evenly spread over 20°.2 of sky within three constellations: Mars in Aquarius, Jupiter in Pisces and Venus in Cetus (Neptune is also in Pisces, mid-way between Mars and Jupiter). This fine celestial equilibrium is even more enhanced by the fact that Jupiter is positioned less than 1° South of the celestial equator (where the declination of a celestial body is 0°) and is only a little over 1° from the First Point of Aries, the point on the ecliptic where the Sun crosses the celestial equator each year at the Spring (Vernal) Equinox.
At 2307 UT on May 17th Mars (mag. +0.8) passes 0°.6 South of the planet Neptune (+7.9) in another planetary conjunction which is ideally placed for Southern hemisphere observers. Neptune is four months away from opposition and is only 0.1 magnitude below its peak brightness for the year. This an ideal opportunity for those who have never seen our most distant Solar System planet to locate it with relative ease, using Mars as a bright locator-beacon. Refer to the planetary conjunctions section below for more details.
Mars enters Pisces through its South-western border at around 9 hours UT on May 19th, with Neptune positioned 58' (0º.96) away to the WNW. Mars completes its passage of the Circlet at 1030 UT on the same day when it passes 6°.7 South of the star TX Psc or 19 Psc (19 Piscium, mag. +5.1v), positioned at the Eastern end of the asterism. It is a red giant variable star with a small irregular brightness variation of between magnitudes +4.8 and +5.2.
Having now passed the Circlet, Mars passes 8º.7 South of the star Psc (Omega Piscium, mag. +4.2), located at the Southern fish's tail, on May 24th. The Red Planet is now approaching Jupiter at a daily rate of about 0º.6. Mars is 2º.6 to the South-west of Jupiter at midnight UT on the 25th, 2º.1 to the South-west of it on the 26th, 1º.5 to the South-west of it on the 27th and 1º.0 South-west of it on the 28th. The waning crescent Moon passes by the two planets from May 24th to 25th.
Mars and Jupiter meet in conjunction at three minutes past midnight UT on May 29th, positioned some 11° to the ESE of the Circlet's centre. The pair are separated by an apparent distance of 0°.6 and the solar elongation is a comfortable 64°. The conjunction is well placed for Southern hemisphere observers but poorly placed for those at higher Northern latitudes. The two planets are easily contained within a wide-field telescope field of view, Mars having increased in apparent size to 6".3 and Jupiter, nearly six times larger at 37".1 across, providing a contrasting visual treat. For more details, refer to the planetary conjunctions section below.
From around late May, the planet Uranus (mag. +5.8) emerges into the dawn sky at the start of its 2022-23 apparition. Currently in the constellation of Aries, the Ram, it adds to a planetary line-up in the morning sky which is becoming increasingly spectacular.
Mars crosses to the North of the celestial equator on May 30th, the planet rising due East across the inhabited world at this time. On May 31st the planet passes 9°.1 North of Cet (Iota Ceti, mag. +3.5), at the tail-end of the Whale. It has been known by the name Deneb Kaitos Shemali but it is mostly not used now because of confusion with the nearby star Diphda ( Cet), the brightest star in the constellation, which was formerly known as Deneb Kaitos. The original Arabic names of these stars translated as 'tail of the whale' to the North ( Cet) and South ( Cet). At about 1830 UT on the same day Mars and Jupiter are about 1°.5 apart and positioned parallel to the celestial equator.
As if six planets were not enough in the existing line-up, in early June Mercury (mag. +2.7) emerges into the dawn sky at the start of its second morning apparition of 2022. As Mars enters Cetus in the early morning hours (UT) of June 3rd, the naked-eye planet observer is presented with a spectacular line-up of five naked-eye planets - plus two binocular ones - in the morning sky. Remarkably, the order of the naked-eye planets on this occasion is the same as their orbital distance from the Sun; Mars is more or less at the centre of the line-up. The line from Mercury to Saturn extends 90°.7, i.e. fractionally over a quarter of the angular circumference of the celestial sphere, stretching from Taurus, the Bull to Capricornus. Even dwarf planet Pluto (mag. +14.4) is technically in the line-up: it is positioned in Eastern Sagittarius, close to its border with Capricornus (if one includes Pluto, the line-up length is about 117°). The line-up continues throughout June, albeit increasing in length with each passing day, ending when Mercury leaves the morning sky.
A Planetary Line-up on June 3rd 2022 sees all seven planets come to within 91° of each other in the morning sky, shown here in the plane of the ecliptic (click on the thumbnail for the full-size image, 16 KB). The planets are indicated by their initial letters and are shown at their correct relative apparent magnitudes (the Sun is shown as an 'S' within a circle). Note that the order of the five naked-eye planets from the Sun matches that of their orbital distances from the Sun (Uranus, Neptune and Pluto are also in order, although out of sequence from the brighter group). All seven planets - plus Pluto - are positioned to the South of the ecliptic. If one includes Pluto the line-up extends to 117°.
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The planetary line-up is ideally viewed from the Southern hemisphere, from where the ecliptic presents a steep angle to the horizon before dawn at this time of the year. The Southern Tropics are perhaps the best latitudes to observe it. For observers located North of about 30° North latitude, however, low altitude and twilight interfere with observation of Uranus and Mercury, which rise much closer to sunrise. At Southern latitudes observers can expect to see Uranus reach 10°-15° in altitude before the dawn twilight overwhelms it, whilst Mercury reaches 13°-17° above the horizon before disappearing from view. The Moon begins to interfere with observation of the fainter planets from June 13th to 23rd (the Moon is Full on June 14th). The Moon passes the line-up between June 18th and 27th; it is waning gibbous when passing Saturn, Last Quarter passing Neptune and waning crescent passing the remaining planets. The angular length of the line-up (from Mercury to Saturn) over the month is as follows: 91°.6 on June 8th, 94°.2 on the 13th, 99°.1 on the 18th, 104°.9 on the 23rd, 112°.1 on the 28th and 121° on July 3rd (when Mercury heads out of view). To include Pluto in the line-up, add 27° to these numbers.
Following their conjunction in late May, the angular distance between Mars and Jupiter increases over the coming days and weeks: at midnight UT on June 3rd the two are 2°.7 apart and by the 6th they are 4°.4 apart.
At 4 hours UT on June 9th Mars re-enters Pisces through its Southern border, having traversed a 4°.3 long track through the North-western corner of Cetus. Jupiter is now 6°.2 to the WSW of the Red Planet. At 9 hours UT on the same day the planet passes 20º.8 North of the aforementioned star Diphda ( Cet or Beta Ceti, mag. +2.0), at the South-western corner of Cetus.
Mars passes 4º.2 South of the star Psc (Delta Piscium, mag. +4.4), positioned about half-way along the Southern Fish of Pisces, on June 11th. The star is one of several which on old star maps mark the long and winding cord between the Northern and Southern Fishes.
At 0243 UT on June 15th the distance between the Earth and Mars is the same as that between the Sun and Mars, at 1.3816 AU (206.6 million kms or 128.4 million miles). Seen from far above the Earth's North pole, the Earth, Mars and the Sun now appear to form an isoscelene triangle in space, with Mars positioned at the apex.
On June 16th Mars passes 3º.1 South of the star Psc (Epsilon Piscium, mag. +4.2), another star in the meandering cord. Positioned 2°.7 to the East of Psc is the double star Revati ( Psc or Zeta Piscium,, mag. +4.9), a Sanskrit name adopted by the IAU in 2017 and derived from an ancient Hindu lunar mansion. Mars passes 1°.7 South of Revati on June 20th. The star comprises two components of magnitude +5.2 and +6.3, separated by a wide 23" (0'.4) and easily split in small telescopes.
Mars reaches perihelion (its closest orbital position to the Sun) on June 21st, positioned at a distance of 1.3813 AU (206.6 million kms or 128.4 million miles) from the Sun.
From around 17 hours UT on June 22nd the waning crescent Moon passes in front of Mars in the third lunar occultation of the apparition. The event is visible in darkness from Antarctica (George V Land, Victoria Land, the Ross Ice Shelf and Marie Byrd Land). For a map and timings of this event, follow the link provided in the Moon near Mars section below.
Mars enters the star chart coverage (above) on June 25th, positioned about 6º South-west of the Piscean border with Aries. The planet attains magnitude +0.5 on the same day, technically making it a zeroth-magnitude object.
Mars passes 1º.3 North of Psc (Mu Piscium, mag.+4.8) on June 26th. On the following day Mars passes 7°.6 South of the star Alpherg ( Psc or Eta Piscium, mag. +3.8), the brightest star in Pisces, then 3°.1 North of Psc (Nu Piscium, mag.+4.4) on June 30th. All three of these stars are located along the cord.
Some seven months after the start of the apparition, observers at high Northern latitudes finally see Mars emerge into the Eastern sky at dawn, although it is seen in continuous twilight. With the planet's elongation now more than 70° West of the Sun, Mars is able to gain sufficient altitude above the horizon to be observed before the twilight becomes too bright to see it.
Table of selected data relating to the brighter part of the Mars apparition of 2021-23, for 0 hrs UT on the dates shown (click on thumbnail for full-size table, 140 KB). The data is listed at 10-day intervals, corresponding with the dates on the star map.
The Central Meridian Longitude (provided for telescopic observers) is the Martian longitude which appears at the centre of the disk when seen from the Earth. A Martian longitude map by Damian Peach showing the surface features can be seen at the ALPO-Japan website (note that the map is shown with South up, matching the inverted view seen through astronomical telescopes). For example, when CM = 290°, Syrtis Major appears at the centre of the disk. The Central Meridian Longitude increases by 14°.6 every hour, so this allowance should be applied for observations at other times (if the result is greater than 360°, subtract 360° to obtain the correct longitude). The Tilt is the angle at which Mars' North pole is tilted towards (+) or away from (-) the Earth; it is the declination of Earth as seen from Mars.
Those wishing to observe Mars telescopically should consider downloading the free 'Mars Previewer II ' software by Leandro Rios, available as a ZIP file at Sky & Telescope, or Kyle Edwards' 'Solar System Imaging Simulator'.
The data for the table was obtained from 'RedShift 5', ''SkyGazer Ephemeris' , 'Mars Previewer II' software and the SETI Institute's Mars Ephemeris Generator. The Martian disk images were derived from NASA's Solar System Simulator. The Martian disks appear at the same scale as those in the Mars Opposition data table here.
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At 0906 UT on July 2nd Mars passes just 12' (0º.2) South of the star Torcular ( Psc or Omicron Piscium, mag. +4.2), which is positioned about one-third of the way along the Northerly section of the cord. The star's long-form name is Torcularis Septentrionalis which is a mis-translation of an original Greek word meaning 'flax', i.e. the aforementioned cord that tied the two fishes' tails together.
Mars passes 9º.5 South of the double star Mesarthim ( Ari or Gamma Arietis, mag. +3.9), on the Western side of Aries, at around 11 hours UT on July 5th. Easily resolved in small telescopes, it comprises two white stars of magnitudes +4.6 and +4.7, separated by 7".5. At 21 hours UT on the same day the planet passes 10º.8 South of the star Sheratan ( Ari or Beta Arietis, mag. +2.6). The name Mesarthim is Arabic in origin but its meaning is unclear, however the star has been associated with Sheratan (Arabic for 'the signs') since ancient times, when the stellar pair were considered to mark the New Year.
Mars passes 7°.8 North of the double star Alrescha ( Psc or Alpha Piscium, mag. +3.8), in neighbouring Pisces, at around 16 hours UT on July 8th. The name Alrescha was standardized by the IAU in 2016, the star having been previously known as Al Rischa, Alrisha or Al Rescha. It comprises two blue-white components of magnitudes +4.1 and +5.1, separated by an angular distance of 1".8 on a roughly East-West orientation. Telescopes of at least 75 mm (3 in) aperture are required to split the pair. Mars enters Aries at around 19 hours UT on the same day.
The Red Planet passes 12°.4 South of the Aries' brightest star Hamal ( Ari or Alpha Arietis, mag. +2.0) on July 10th. In 2011 the star was found to have an extra-solar planet or exoplanet (a planet outside our own Solar System) orbiting around it. Mars passes between Alrescha and Hamal on July 9th.
On July 21st Mars is involved in the fourth lunar occultation of the apparition. From around 14 hours UT the waning crescent Moon passes in front of the planet, an event which is visible in darkness from Northern Japan (Northern Honshu and Hokkaido) and in twilight from Eastern Russia. Follow the link below for a map and timings of the event.
On July 24th Mars passes 10°.8 North of Kaffaljidhma ( Cet or Gamma Ceti, mag. +3.6) in Cetus, a double star comprising yellow and blue components of magnitude +3.5 and +7.0 separated by just 2".7. A telescope with an aperture of at least 60 mm (2½ inches) and high magnification is required to split them. The name is Arabic for 'the palm of the hand'.
In late July observers at high-Northern latitudes are now seeing Mars rising in a dark sky, the planet reaching over 30° in altitude in the ESE before disappearing from view in the twilight. Elsewhere the planet reaches 45° high in the South-east at latitude 50° North, 66° high in the South-east at latitude 30° North, 72° high in the NNE at the Equator and 40° high in the North at 35° South.
On July 27th Mars passes 12º.6 South of the variable and double star Bharani (41 Ari or 41 Arietis, mag. +3.6), named after the second lunar mansion in Hindu astrology. It is another name which was adopted by the IAU in 2017. Two degrees to the NNW of Bharani, in the Northernmost realm of Aries, is the star Lilii Borea (39 Ari or 39 Arietis, mag. +4.5), a Latin name meaning 'Northern Lily'. The name was formally recognised by the IAU in 2017 and it first appeared in a 1757 star catalogue compiled by the French astronomer Nicolas-Louis de Lacaille (1713-1762). The lily to which he referred was the short-lived constellation Lilium, the Lily, a fleur-de-lis placed in this part of the sky by another Frenchman, Ignace-Gaston Pardies (1636–1673), in honour of King Louis XIV. Mars passes 14º.7 South of Lilii Borea on July 26th.
On July 30th the planet passes 6º.0 South of Ari (Epsilon Arietis, mag. +4.6), which is also both a double star and a variable star. Its two white components are magnitudes +5.2 and +5.5 and are separated by just 1".5, requiring telescopes of at least 100 mm (4 in) and high magnification in order to split them.
Mars passes 11°.5 North of the red giant star Menkar ( Cet or Alpha Ceti, mag. +2.5) on July 31st. Binoculars show an apparent blue companion star of magnitude +5.6 close by, but this is only a line-of-sight effect; the star is actually over six times more distant than Menkar. The name is Arabic for 'the nose', i.e. the nose of the Whale.
Mars at Minimum Phase imaged by Paulo Casquinha (Palmela, Portugal) in June 2020 when the planet was in the morning sky (click on the thumbnail for a larger image, 4 KB). Mars showed an 84% illuminated phase and was 10".5 in diameter. Western quadrature had taken place two weeks earlier (Image: Paulo Casquinha / ALPO-Japan).
On August 1st Mars passes 1º.3 South of Uranus in the sixth and final observable conjunction of the 2021-23 apparition. This is the only one of the six which is favourable for Northern hemisphere observers, with the exception of those at higher Northern latitudes. As Mars passes the ice giant its daily rate of motion is some 32 times faster. Uranus will reach opposition in November, when it will shine 0.2 magnitudes brighter.
On August 4th Mars passes 3º.6 South of the star Botein ( Ari or Delta Arietis, mag. +4.3) which on older star maps marked the hind leg of the Ram.
Mars enters Taurus, the Bull, on August 9th, the constellation in which it will spend the most time in the 2021-23 apparition. On the following day Mars attains its minimum phase for the apparition, at 84.7%, causing the planet to appear notably gibbous when seen through telescopes. The Red Planet now shines at magnitude +0.1, its apparent diameter being 8".6 and its solar elongation 83º East.
Between August 17th and 19th the planet passes several degrees South of the constellation's most famous asterism known as the Pleiades or Seven Sisters (M45). Mars passes 5º.8 South of the cluster's brightest Western star (Electra, mag. +3.7) at around 17 hours UT on the 17th, completing its passage at around 13 hours UT on the 19th, when it passes 5º.5 South of the cluster's brightest Eastern star (Atlas, mag. +3.6).
At 6 hours UT on August 24th Mars passes 6°.7 North of the eclipsing binary star Tau (Lambda Tauri), positioned at the upper 'chest' of the Bull figure, whose magnitude varies from ca. +3.5 to +4.0 over a period of four days. At 18 hours UT on the same day Mars is positioned at precisely 1.0000 AU from the Earth, i.e. the same distance as the average distance of the Earth from the Sun (149.5 million kms or 92.9 million statute miles). Viewed from a point in space far above the Earth's North pole, the Earth, Mars and the Sun would now appear to form an isosceles triangle, with Earth positioned at the apex.
Mars reaches Western quadrature at 0532 UT on August 27th, when it is positioned 90° West of the Sun. The planet now shows an illuminated phase of 84.9%, frcationally larger than it showed at minimum phase on August 10th. If the orbit of Mars was perfectly circular, the quadrature and minimum phase dates would always coincide, however since the planet's orbit is eccentric, they often do not. At Western quadrature Mars is rising 7½ hours before sunrise at latitude 60° North, 6¾ hours before sunrise at 40° North, 6¼ hours before the Sun at the Equator and 5¾ hours before the Sun at 35° South. Directionally, Mars rises towards the North-east at high Northern latitudes and towards the ENE at latitudes further South. At latitudes North of the Equator, the planet has not yet reached the local meridian as it disappears from view in the dawn twilight; to the South of the Equator the planet has already crossed the local meridian when it disappears from view. At 2152 UT on Western quadrature day Mars passes 46' (0°.76) South of the star 1 Tau (Omega-1 Tauri, mag. +5.5), positioned in central Taurus some 6°.9 to the South-east of the Pleiades and 1°.3 South of the ecliptic.
Between September 1st and 9th Mars passes several degrees to the North of a large star cluster called the Hyades, a distinct 'V'-shaped grouping of stars which form the head of the Bull. The cluster comprises around 400 stars spread over an exceptionally large area of about 5° of the sky. On September 1st Mars passes 4°.5 North of the star Prima Hyadum ( Tau or Gamma Tauri, mag. +3.6), positioned at the apex of the 'V'. Before the name was standardized by the IAU in 2017, the star was known variously as Primus Hyadum or Hyadum I. On September 3rd Mars passes 2°.7 North of Secunda Hyadum (1 Tau or Delta-1 Tauri, mag. +3.7), a triple star system positioned about half-way along the Northern arm of the cluster. Before IAU standardization the star was also known as Secundus Hyadum or Hyadum II.
Positioned a few degrees North of the Hyades is a grouping of stars of between 4th and 6th magnitude which straddle the ecliptic. On September 4th Mars passes 1°.9 South of the stars 1 Tau (Kappa-1 Tauri, mag. +4.2) and 2 Tau (Kappa-2 Tauri, mag. +5.2). Later that day the planet passes 2°.3 South of Tau (Upsilon Tauri, mag. +4.3). At 0030 UT on September 5th the Red Planet passes 2°.5 South of 72 Tauri (mag. +5.5). Mars will come to within 4" (0°.001) of this star in March 2036.
Positioned along the Northern arm of the Hyades is the star Ain ( Tau or Epsilon Tauri, mag. +3.5), which on older star maps marked one of the Bull's eyes. Mars passes 1°.3 North of the star at 15 hours UT on September 5th. At the same moment the planet passes 4°.6 North of Chamukuy (2 Tau or Theta-2 Tauri, mag. +3.7), positioned about half-way along the Southern arm of the cluster. The name is that of a small bird in Yucatec Mayan culture and it was adopted by the IAU in 2017. The star forms a naked-eye yellow-white double with 1 Tau (Theta-1 Tauri, mag. +3.8), positioned some 5'.6 (0°.09) to the North.
Also on September 5th, Mars reaches 10".0 in angular diameter, positioned about 94° West of the Sun. The planet is now brightening significantly with each passing week, its pale orange coloration seemingly more obvious than in the preceding months. For telescopic observers, the planet is now at a sufficiently large apparent size for significant surface detail to be seen and for a regular observing campaign to begin.
On September 9th Mars passes 4°.3 North of Aldebaran ( Tauri, mag. +0.9), the brightest star in Taurus, positioned at the South-eastern corner of the 'V' and marking the other 'eye' of the Bull. Aldebaran appears orange-red to the naked-eye since it is a red giant star. It appears to be part of the cluster but in fact, it is not a physical member of the Hyades group; its appearance in the cluster is purely a line-of-sight effect. The Hyades lie at a distance of about 150 light years from Earth whereas Aldebaran is much closer, at 68 light years.
On September 12th Mars passes 1°.8 South of Tau (Tau Tauri, mag. +4.2), another star which, like Aldebaran, is not part of the Hyades group. Positioned at the base of the Bull's Northern horn, it is a multiple-star system and a member of an obscure open cluster known as Alessi 51.
Prior to 2022, Mars last reached opposition in the tail of Pisces in October 2020 (click on the thumbnail for the full-size photo, 33 KB). This photograph, taken by the writer, shows the Red Planet two days before opposition day, when it shone at magnitude -1.8. Mars was positioned a short distance WSW of the star μ Psc (Mu Piscium, mag. +4.8). Click here (18 KB) to see an annotated version of the photograph.
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From mid-September Mars passes to the North of Orion, the Hunter, perhaps the most recognisable constellation in the night sky. Orion emerged into the dawn sky in July/August and is now in the early stage of its seasonal appearance, rising due East in the early morning hours. The Red Planet passes North of Orion's bow, comprising the stars Tabit (3 Ori, or Pi-3 Orionis, mag. +3.2) at the centre, 1 Ori (Pi-1 Orionis, mag. +4.6) at the top and 6 Ori (Pi-6 Orionis, mag. +4.5) at the base, between September 16th and 20th.
Located to the North-east of Taurus is the six-sided figure comprising the stars of Auriga, the Charioteer. Mars passes 11°.3 South of Hassaleh ( Aur or Iota Aurigae, mag. +2.5), at the South-western corner of the constellation, on September 19th.
Mars passes 21' (0°.35) North of Tau (Iota Tauri, mag. +4.6), positioned in the central space between the Bull's horns, at 0420 UT on September 23rd.
Mars passes 23°.3 South of Auriga's brightest star Capella ( Aur or Alpha Aurigae, mag. +0.1) on October 1st. Capella comprises two yellow stars orbiting each other; it is a spectroscopic binary, meaning that the secondary star is so close to its parent star that it can only be detected by observing Doppler shifts in its spectral lines. Capella is the third brightest star in the Northern celestial hemisphere and the sixth brightest star in the entire night sky. It is often catches the eye of observers in mid-Northern latitudes during summer nights, when it is seen low over the Northern horizon. Capella is circumpolar from latitudes North of 44° North, meaning that from these latitudes it is always above the horizon.
Mars passes 26' (0°.43) North of 109 Tau (109 Tauri, mag. +4.9) at 1250 UT on October 3rd, then 16°.6 North of Bellatrix ( Ori or Gamma Orionis, mag. +1.6), the North-western corner star of Orion's distinctive quadrilateral, on October 7th.
Mars' Eastward motion against the background stars has slowed considerably in recent weeks, from 0º.46 per day in mid-September to just 0º.28 per day by the second week of October. Its Eastward motion will cease completely at month's end.
On October 9th Mars passes 5°.7 South of the star Elnath ( Tau or Beta Tauri, mag. +1.6), which is located at the tip of the Bull's Northern horn. The name was standardized by the IAU in 2016, previous versions of the name being spelled Al Nath, El Nath or simply Nath.
At 1350 UT on October 17th Mars passes 1°.2 North of the Crab Nebula (M1 or NGC 1952), the gaseous remnant of a supernova which exploded in 1054 AD. It is a faint object, just visible in binoculars under dark skies and an elongated wisp when seen through telescopes. The nebula was first observed in 1731 by English physician and amateur astronomer John Bevis (1695-1771) but it was named in 1848 by William Parsons (1800-1867), third Earl of Rosse, who thought it resembled a crab's claw when he saw it through his 72-inch telescope at Birr Castle in Ireland.
Mars crosses to the North of the ecliptic on October 20th, then on the 22nd passes 2°.3 North of the star Tianguan ( Tau or Zeta Tauri, mag. +2.9v), which marks the tip of the Bull's Southern horn. The name, adopted by the IAU in 2017, is derived from Chinese astronomy, in which the star is known as the Celestial Gate, part of an asterism contained within a mansion called Bì Xiù ('the Net').
On October 30th Mars' Eastward motion ceases as the planet reaches its Eastern stationary point, positioned 2º.7 to the NNE of Tianguan. Over the next few days its apparent motion changes direction from Northwards to Westwards as the planet turns retrograde - a motion which will continue for the next 2½ months.
Having reversed its motion against the background stars, Mars begins to pass several of the celestial bodies that it had passed over the previous two months, but in reverse order. Moving retrograde, the planet passes 3º.0 North of Tianguan on November 6th, then 2°.3 North of the Crab Nebula on the 11th. On the 19th the planet passes 3°.9 South of Elnath, then 18°.5 North of Bellatrix on the 20th. On the 24th it passes 2°.7 North of 109 Tauri, then 21°.0 South of Capella on the 25th.
At 0217 UT on December 1st Mars reaches its closest point to the Earth for this apparition, at 0.5447 AU distant (81.4 million kms or 50.6 million miles), a point known as the perigee (or, in the specific case of Mars, the periareion). The Red Planet now shines at magnitude -1.9 (its brightest for the apparition) and its apparent size is 17".2 (its largest for the apparition). This is double the size that it was in mid-August and triple the size that it was in late April.
On December 4th Mars passes 3º.4 North of Tau, this time moving retrograde. From December 7th to the 12th the planet passes North of Orion's bow again.
Mars reaches opposition to the Sun at 0536 UT on December 8th in Northern Taurus, positioned 9º.9 to the North-east of Aldebaran and 16º East of the Pleiades. The planet is now directly opposite the Sun in the sky (solar elongation = 180°), its illuminated phase is 100% and it shines at magnitude -1.86. Mars is now the third brightest object in the night sky (after the Moon and Jupiter), outshining all of the stars around it. However, due to the eccentricity of Mars' orbit, its apparent disk size is not quite as large as it was at its closest passage a week earlier. Lying at a distance of 0.5495 AU from the Earth, Mars is now about 755,400 kms (469,400 miles) more distant than it was at perigee. Consequently its apparent size is fractionally smaller, at 17".0. On opposition day Mars is slowly moving Westwards at a rate of about 0º.4 per day.
Mars at Opposition in October 2020 imaged by Anthony Wesley (Rubyvale, Australia) (click on the thumbnail for a larger version, 7 KB). The small Southern Polar Cap (bottom of picture) is a consequence of the planet having recently experienced high summer in its Southern hemisphere. The slightly curved feature at the centre-right of picture is Sinus Sabaeus and Sinus Meridiani. Wesley used a 415mm (16-inch) Newtonian reflector telescope fitted with a CMOS camera (Image: Anthony Wesley / ALPO-Japan).
At opposition, a superior planet rises around sunset, is visible throughout the night and sets around sunrise. Its highest point in the sky is reached when it crosses (transits) the observer's meridian at local midnight (due South at midnight in the Northern hemisphere; due North at midnight in the Southern hemisphere). At the 2022 opposition Mars has a declination of +24°.9; as such, the current opposition favours Northern hemisphere observers, where Mars transits the meridian at a high altitude (at latitude 24º 54' North the planet transits at the zenith, directly above the observer's head). A list of meridian transit altitudes and directions of the planet at opposition for various latitudes over several Martian oppositions is given in the table below.
On opposition day, Mars is experiencing late Winter in its Northern hemisphere and late Summer in its Southern hemisphere. The planet's Southern Pole is tipped towards the Earth at an angle of about 5º, giving us a shallow view of its Southern Polar Cap (SPC). Mars is positioned at a heliocentric longitude of 75º ( = 75°) and the areocentric longitude of the Sun (Ls) is 350°. The Martian Year is 36, the Martian Month is 12 and opposition day equates to Sol Number 651 on Mars. The equivalent Earth date on Mars - called the Martian Date (MD) - is March 11th. All the terms given in this paragraph are explained in more detail on the Martian seasons page.
At the 2022 opposition, Mars is about half as bright as it was when it previously reached opposition in October 2020 and its apparent disk diameter is about three-quarters of the size. Nonetheless it is the largest apparent disk size that the planet will show to the Earth before the year 2033. Mars is now past its period of perihelic oppositions (where the planet is close to the perihelion point of its orbit) and in 2022 is roughly mid-way between perihelic and aphelic oppositions (for more details, see the Mars oppositions page).
One-and-a-half hours before Mars reaches opposition, at 0408 UT, a Full Moon occurs. This particular Full Moon is significant because it occults the planet, blocking it from view for up to 72 minutes (the exact period depending upon the observer's location within the visibility track). This is easily the most important lunar occultation to take place in the planet's 2021-23 apparition since it is visible from a substantially populated region of the world and, from many locations inside the visibility track, it takes place at a relatively convenient time. The event is visible in darkness from the North-eastern Pacific Ocean (not Hawaii), Canada, the USA (except the South-eastern states and most of Alaska), North-western Mexico, Greenland, the North Atlantic Ocean, Iceland and Svalbard. It is seen in twilight/darkness from Europe (including Scandinavia but excluding the far South-eastern countries), Northern Morocco, Northern Algeria, Tunisia and Western Russia. The occultation begins at 2 hours UT on the 8th (equating to evening on December 7th on the West coast of North America) and ends at 6 hours UT (the pre-dawn hours over Europe and North Africa). Follow the link below for a map and approximate timings of the event.
A Lunar Occultation of Mars takes place on the night of the Martian opposition on December 7th-8th 2022, when the Moon is at Full phase. This is a simulation of how the event may appear from San Francisco, USA, moments before the planet's disappearance behind the Moon's Eastern limb at 18:34 PST on December 7th (click on the thumbnail for the full-size image, 56 KB). San Francisco - one of the first cities to witness the event - is positioned close to the centre-line of the visibility track and will see Mars disappear for 61 minutes.
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Opposition day having passed, Mars' solar elongation changes from Westerly to Easterly and the angle reduces below 180°. By December 15th - one week after opposition - the planet's solar elongation has reduced to 170° East of the Sun.
Mars continues its retrograde motion through Northern Taurus. On December 17th the planet passes Tau again, on this occasion passing 1°.9 North of the star (not South of it, as it did in mid-September). The planet then passes 8º.3 North of Aldebaran on December 22nd, a full 4° further North than its previous passage of the star in early September.
On December 26th Mars passes the position in its orbit which marks the Spring Equinox in the Northern hemisphere (Autumnal Equinox in the Southern hemisphere). For a diagram of how the Martian seasons compare with those of the Earth, see the Martian seasons page.
Still moving retrograde, Mars passes 5º.4 North of Ain on December 28th and, at the same time, 8°.7 North of Chamukuy. The planet's Westward motion has slowed significantly since opposition day since it is now approaching its Western stationary point.
In the closing days of 2022 Mars passes the cluster of fainter stars which are positioned to the North of the Hyades. On December 30th the planet passes 1º.6 North of 72 Tau, then 1º.7 North of Tau on December 31st. Back in early September the planet had passed to South of these stars.
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On January 2nd Mars passes 2º.2 North of the stars 1 and 2 Tau, moving retrograde.
On January 3rd another lunar occultation of Mars takes place, this being the sixth of the planet's 2021-23 apparition. From around 18 hours UT the waxing gibbous Moon occults the planet, the event being visible in twilight/darkness from Southern Africa (roughly South of a line from the D. R. Congo across to the Gulf of Aden), along with Madagascar and the Southern Indian Ocean. For a map and approximate timings of the event, follow the link below.
Moving retrograde, Mars passes 6º.9 North of Secunda Hyadum, on the Northern arm of the Hyades cluster, on January 6th; this is 4º.2 further North than its previous passage of the star in early September 2022.
Mars reaches its Western stationary point on January 13th, positioned 8º.6 North-west of Aldebaran and 8º.1 East of the Pleiades cluster. The planet's motion now turns direct once more, as it will continue to do so for the remainder of the apparition.
Now moving Eastwards, Mars begins to pass the numerous stars which it has already passed on two occasions before. On January 17th it passes 6º.9 North of Secunda Hyadum, then 2º.2 North of the stars 1 and 2 Tau on the 23rd. The planet passes 1º.7 North of Tau on the 25th, 1º.5 North of 72 Tau on the 26th and 5º.4 North of Ain (8°.7 North of Chamukuy) on the 28th. Note that, from its Western stationary point in mid-January through to around mid-February, the angular distance between Mars and the stars that it has previously passed is about the same; this is because the planet is more or less retracing the path that it took against the background stars whilst in retrograde motion (from around the second week in December through to mid-January). This path is about 6º further North than the path the planet took in the approach to its Eastern stationary point between early and mid-September 2022 (for more information on the loops and zig-zags described by the planets in the night sky, see the Planet Movements page).
By the third week of January Mars has faded back to minus zeroth magnitude (-0.5) and its apparent diameter has reduced to 12" - two-thirds of the size that the planet had appeared at its closest approach back in early December.
From around 2 hours UT on January 31st Mars is occulted by the Moon for the seventh occasion during the planet's apparition. This lunar occultation is visible in darkness from the Eastern central Pacific Ocean, the Southern USA, Central America, the Western Caribbean (Cuba and Jamaica), The Bahamas and North-western South America (Ecuador, Western Colombia and Northern Peru). To see a map and approximate timings of the event, follow the link below.
Moving direct, Mars passes 8º.3 North of Aldebaran on February 5th, the apparent size of the Martian disk falling below 10" three days later.
On February 10th Mars passes 1°.9 North of Tau again - the same distance by which it passed this star in mid-December.
In mid-February Mars' apparent magnitude returns to positive (+0.0). At 7 hours UT on February 14th Mars is positioned at precisely 1.0000 AU from the Earth, i.e. the same distance as the average distance of the Earth from the Sun (149.5 million kms or 92.9 million statute miles). When the planet was last 1.0000 AU from Earth in the previous August its distance from Earth was slowly reducing; now the planet's distance is slowly increasing. As was the situation six months earlier, when viewed from a point in space far above the Earth's North pole, the Earth, Mars and the Sun would again appear to form an isosceles triangle, with Earth positioned at the apex.
Between February 16th and 22nd the Red Planet passes North of Orion's bow once more, moving direct. Mars passes 7°.9 South of Hassaleh in Auriga on February 21st; the planet is positoned between Orion's bow and Hassaleh on February 20th. Mars passes 3°.6 North of Tau on February 24th.
On February 28th the waxing gibbous Moon passes in front of Mars in the penultimate lunar occultation of the planet's 2021-23 apparition. The event is visible in darkness from Eastern Greenland and Iceland and in twilight from Northern Scandinavia and Svalbard. Follow the link below to see a map and timings of the event.
In the first two weeks of March, Mars continues its journey through North-eastern Taurus, passing stars which it has previously passed on two occasions during the last five months: 20°.4 South of Capella on March 4th; 3°.4 North of 109 Tau on the 5th; mid-way between Capella and Bellatrix at 9 hours UT on the 7th; 19°.2 North of Bellatrix itself at 1 hour UT on the 9th; 3°.0 South of Elnath at 1630 UT on the 9th; 3°.5 North of the Crab Nebula on the 13th and finally, at 10 hours UT on the 15th, 4°.5 North of Tianguan.
Also on March 15th, Mars attains its minimal illuminated phase for the Eastern elongation period of the apparition, at 89.7%. Note that this is not the minimum phase for the whole apparition - this took place in the previous August, when the phase was 5% smaller. The following day at 18 hours UT Mars reaches Eastern quadrature, when it is positioned 90° East of the Sun; unlike in August, when the minimum phase and quadrature dates were separated by a few weeks, on this occasion minimum phase falls only a day after the planet attains minimum phase. Mars now shines at magnitude +0.7 and its apparent diameter is 7".2. Unlike at Western quadrature, the illuminated part of the planet's disk faces Westwards (not Eastwards, as before) because it is now positioned to the East of the Sun when seen from the Earth. At around 23 hours UT on the same day Mars is positioned roughly mid-way between the bright stars Capella and Betelgeuse ( Ori or Alpha Orionis, mag. +0.7v), the latter being an orange-red variable star at the North-eastern corner of Orion's quadrilateral.
Mars at Minimum Phase sketched by Chris Nuttall (York, UK) in January 2021 during the planet's evening sky appearance (click on the thumbnail for a larger version, 6 KB). Nuttall used a 300mm (12-inch) Newtonian reflector telescope at 416x magnification. The dark wavy feature just above the centre of picture is the Mare Sirenum and Mare Cimmerium (Image: Chris Nuttall / ALPO-Japan).
On March 19th Mars attains its most Northerly declination for this apparition ( = +25° 36' 36" or +25°.609), the most Northerly declination attained by the planet since January 2008 and before February 2025. Mars now sets at its most Northerly point along the local horizon, the actual point of setting depending upon the observer's latitude. This will be towards the North-west at higher Northern and Southern latitudes and towards the WNW at most other inhabited latitudes. Mars is now setting ten hours after the Sun at latitude 60° North, 7¾ hours after the Sun at 40° North, six hours after sunset at the Equator and 4½ hours after sunset at 35° South. For all inhabited locations on Earth, Mars has already crossed the local meridian when it comes into view in the dusk twilight.
Mars passes 18°.3 North of Betelgeuse on March 23rd; at magnitude +0.8 the Red Planet shines at nearly the same brightness as the red giant star. The Red Planet passes North of Orion's club, topped by the stars Chi-1 Orionis (1 Ori, mag. +4.4) and Chi-2 Orionis (2 Ori, mag. +4.6), between March 23rd and 28th.
Mars enters Gemini, the Twins, on March 26th, passing 2°.3 North of the star 1 Gem (1 Geminorum, mag. +4.2), at the Western end of the constellation, on the 28th. A short distance North-east of 1 Geminorum is the open star cluster M35 (NGC 2168). The cluster has an apparent diameter of 30' (about the apparent size of the Full Moon) and contains over 400 stars(!) It can be glimpsed with the naked-eye as a misty patch of light on a dark, clear night. Mars passes 1°.2 North of the cluster's centre between 22 hours UT on the 29th and 21 hours UT on the 30th.
Mars passes 2°.9 North of Propus ( Gem or Eta Geminorum, mag. +3.5v), also referred to as Tejat Prior before IAU standardization, on April 1st. On April 5th the planet passes 2°.8 North of the star Tejat ( Gem or Mu Geminorum, mag. +3.0v), which together with Propus marks the Northern twin's lower left leg. Before IAU standardization the star was known by the name of Tejat Posterior, among others. On April 12th the planet passes 8°.8 North of Alhena ( Gem or Gamma Geminorum, mag. +1.9), at the ankle of the Southern Twin's left leg. At 1851 UT on April 14th Mars passes 9' (0°.15) South of Mebsuta ( Gem or Epsilon Geminorum, mag. +3.0), a yellow supergiant double star positioned at the 'groin' of the Northern Twin. On April 22nd at 1717 UT the planet passes 18' (0°.3) North of Gem (Omega Geminorum, mag. +5.2), which is positioned roughly at the centre of the constellation.
At 0720 UT on April 22nd the distance between the Earth and Mars is the same as that between the Sun and Mars, at 1.6585 AU (248.1 million kms or 154.1 million miles). The configuration resembles that which took place in June of the previous year, although the Earth-Mars distance is greater on this occasion. Seen from far above the Earth's North pole, the Earth, Mars and the Sun again appear to form an isoscelene triangle in space, with Mars positioned at the apex.
At around 0820 UT on April 23rd Mars forms an isosceles triangle with Gemini's two luminaries Castor ( Gem or Alpha Geminorum, mag. +1.6) and Pollux ( Gem or Beta Geminorum, mag. +1.1), Mars being positioned at the apex. The long sides of the triangle measure a little under 10° and the angular distance of the short side (from Castor to Pollux) is 4°.5. At magnitude +1.2 Mars shines slightly brighter than Pollux at this time. The temporary celestial triangle points South-westwards towards Northern Orion. Later that same day Mars passes 3°.9 North of the variable and optical double star Mekbuda (Gem or Zeta Geminorum, mag. +3.9v), which is positioned at the upper left leg of the Southern Twin (Pollux).
Venus, currently at magnitude -4.0 in Taurus, has been a prominent 'Evening Star' since January, located far to the West of Mars. Since that time it has been slowly closing the gap between the two; at midnight UT on April 25th Venus is 30° to the West of the Red Planet. Over the next two months Venus will continue to close in on Mars but on this occasion they will not reach conjunction.
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Mars passes 2°.0 North of the double star Wasat ( Gem or Delta Geminorum, mag. +3.5) on April 30th. On May 6th Mars passes 8°.4 South of Castor, which is Gemini's second-brightest star. On May 8th the planet passes 11°.3 South of another star whose 'new' name was officially recognised by the IAU in 2017. Jishui ( Gem or Omicron Geminorum, mag. +4.9) is positioned close to the constellation's Northern border with Lynx. The name comes from ancient Chinese astronomy, Jishui being the water flow from the River Beihe which was used for wine-making and brewing. In the Chinese night sky the river was identified with the stars Castor, Pollux and nearby Gem (Rho Geminorum, mag. +4.2).
Also on the 8th, Venus moves into Gemini, positioned 22°.5 West of Mars at midnight UT. Venus is closing in on the Red Planet at a daily rate of about 0°.6 at this time.
On May 10th at 8 hours UT Mars (mag. +1.4), the star Gem (Kappa Geminorum, mag. +3.5) and Gemini's brightest star Pollux line up along 5°.0, aligned roughly NNE-SSW. To the SSW the line points to the bright star Procyon ( CMi or Alpha Canis Minoris, mag. +0.5) in the constellation of Canis Minor, the Lesser Dog, located some 18° to the South of Mars. Mars passes 1°.4 South of Gem itself three hours later, then 5°.1 South of Pollux ten hours thereafter.
At around 20 hours UT on May 16th Castor, Pollux and Mars form a line 11°.1 long, orientated NNW-SSE, pointing Southwards towards the head of Hydra, the Water Snake, which is positioned 20° to the SSE of Mars.
From higher Northern latitudes, twilight begins to interfere with observation of Mars from its first appearance at dusk through to its setting in the North-west. The Sun, more than 60° to the West of the Red Planet, has just crossed into Taurus and is heading towards its most Northerly point on the ecliptic, which will mark the Northern hemisphere's summer solstice in one month's time. In mid-May the altitudes and directions of the planet, as it becomes visible in the dusk twilight, are: 27° high in the West at 60° North, 46° high in the West at 40° North, 54° high in the North-west at the Equator and 31° high in the NNW at 35° South.
Mars enters Cancer, the Crab, on May 17th, passing 14' (0°.23) North of the star 2 Cnc (Mu-2 Cancri, mag. +5.3), in Eastern Cancer, at 0503 UT on May 20th. The star 1 Cnc (Mu-1 Cancri, mag. +6.0) is located 1°.1 to the NNW of 2 Cnc.
Table showing the position and apparent magnitude of Mars for the latter part of the 2021-23 apparition (click on thumbnail for full-size table, 17 KB). As in the first table, the magnitudes, diameters and solar elongations refer to the middle of the period in question.
On May 23rd Mars passes 12°.3 North of Cancer's brightest star Tarf ( Cnc or Beta Cancri, mag. +3.5), at the South-western corner of the constellation's lambda-shaped () figure. Prior to IAU standardisation in 2018 it was known by the name Altarf, which is Arabic for 'the End', i.e. the end of the Crab's leg.
Mars reaches aphelion (its most distant orbital position from the Sun) on May 30th, when it is positioned at a solar distance of 1.6659 AU (249.2 million kms or 154.8 million miles).
Between 3 hours UT on June 2nd and 21 hours UT on June 3rd, Mars passes through the star cluster Praesepe, also known as the Beehive Cluster (M44 or NGC 2632). Under dark, rural skies it is visible to the naked-eye as a hazy patch of light and in city locations it is easily seen in binoculars. 'Praesepe' is a Latin word meaning 'manger', so named after the Nativity story in the Christian Bible; indeed, another less commonly used name for the cluster is the Manger. Mars passes just to the North of the cluster's centre at around 22 hours UT on the 2nd.
Venus, now magnitude -4.2, crosses into Cancer at 7 hours UT on June 3rd, positioned 10º.1 to the WNW of Mars. Venus continues to narrow the gap with the Red Planet, its rate of approach reducing slightly to 0°.4 per day.
Also present in the Nativity story were two donkeys, and they are represented in the night sky by two fourth-magnitude stars. Asellus Borealis ( Cnc or Gamma Cancri, mag. +4.6), the Northern donkey, and Asellus Australis ( Cnc or Delta Cancri, mag. +3.9), the Southern donkey, are separated by 3º.3 and they flank the Praesepe cluster in central Cancer. Mars passes 1°.8 South of Asellus Borealis at around 02 hours UT on June 4th and 1°.4 North of Asellus Australis at around 16 hours UT on the same day. The planet passes between the two stars at 1134 UT. Also on June 4th, Venus attains its greatest solar elongation (45°.4 West), positioned 9°.6 to the WNW of Mars.
Mars passes 9°.2 South of Cnc (Iota Cancri, mag. +4.0), at the top of the Crab's lambda-shaped figure, on June 5th.
From around the second week of June, Mars becomes lost from view in the dusk twilght from higher Northern latitudes, as midsummer approaches. Slightly further South, observers at mid-Northern latitudes now only have a viewing window of about three weeks in which to view the planet.
Mars leaves the star chart coverage (above) on June 6th. On June 11th the planet passes 6º.7 North of Acubens ( Cnc or Alpha Cancri, mag. +4.3), a double star positioned towards the South-eastern corner of the constellation.
Venus is 7°.1 WNW of Mars at midnight UT on June 12th, 6°.2 WNW of it on the 15th and 5°.3 WNW of it on the 18th.
Mars enters Leo, the Lion, at 11 hours UT on June 20th, with Venus trailing 4°.8 to the WNW. Venus' path against the background stars has now begun to curve Southwards, slowing its approach rate towards the Red Planet slightly.
On June 24th Mars passes 6°.8 South of the star Alterf ( Leo or Lambda Leonis, mag. +4.3), which is positioned at the 'jaw' of the Lion's head.
Venus enters Leo on June 26th, positioned 3°.7 to the WNW of Mars. It is 3°.6 to the WNW of the Red Planet at midnight UT on the 27th.
On June 28th Mars passes 5°.3 North of the star Subra ( Leo or Omicron Leonis, mag. +3.5), positioned at the fore-leg of the Lion, although the name is Arabic for a mane or shoulder. From June 30th through to July 15th the planet passes to the South of the Sickle of Leo, at the Western end of the constellation (it forms the head and chest of the Lion); to the naked-eye it appears as a backward question-mark (). The passsage of the Sickle begins as Mars passes 8°.9 South of the star Ras Elased Australis, also known as Algenubi ( Leo or Epsilon Leonis, mag. +2.9), at the upper North-western end ('pointed end') of the sickle, on June 30th.
Venus comes to within 3°.5 of Mars on July 1st, the two planets being situated in Western Leo. Around this time observers at mid-Northern latitudes begin to lose sight of the Red Planet as it heads into the dusk twilight.
Mars passes 11°.7 South of the star Rasalas ( Leo or Mu Leonis, mag. +3.9), at the top of the sickle, on July 3rd. Venus moves to the South of the ecliptic on July 4th, at which time it is 3°.7 to the West of Mars; it is 4°.1 to the West of the Red Planet at midnight UT on the 8th and 4°.8 West of it on the 11th. Venus attains its maximum brightness for the planet's 2023 evening apparition on July 9th, when it reaches magnitude -4.3.
Mars passes 42' (0°.7) North of Leo's brightest star Regulus ( Leo or Alpha Leonis, mag. +1.4), positioned at the base of the Sickle, on July 10th. The Eastern end of the Sickle is marked by the star Algieba (1 Leo or Gamma-1 Leonis, mag. +2.3), which is at the base of the Lion's neck (although the name is Arabic for 'the forehead'). It is a double star with golden-yellow components (1 Leo and 2 Leo) of magnitudes +2.3 and +3.6, separated by an angular distance of 4".7. Mars passes 8°.2 South of the star - thus completing its passage of the Sickle - on July 15th. Venus is now 6°.2 to the WSW of Mars and pulling further away from it.
Farewell to Mars (click on the thumbnail for a larger version, 2 KB) As the 2019-21 apparition drew to a close some determined amateurs continued to image Mars under difficult observing conditions. Using his 355mm (14-inch) Schmidt-Cassegrain reflector, Simon Kidd (Cottered, UK) captured this image in July 2021 when Mars was only 30° from the Sun and just 3".8 in diameter (Image: Simon Kidd / ALPO-Japan).
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In mid-July Mercury (mag. -0.6), currently in Cancer, emerges into the dusk sky for its second evening apparition of 2023, positioned some 25° to the WNW of Mars. This particular evening apparition favours Southern hemisphere observers, from where the ecliptic is inclined at a steep angle to the Western horizon at dusk at this time of year. Over the next few weeks Mercury approaches Mars, moving against the background stars at 2½ times the daily rate of motion of the Red Planet. Meanwhile Venus slowly moves away from Mars, its solar elongation reducing as it closes in on the Sun.
At 22 hours UT on July 20th Mars passes 0°.9 North of Leo (Rho Leonis, mag. +3.8), with Venus 8°.8 to the West and Mercury (mag. -0.3) 18°.6 away to the WNW. Also on the 20th, Venus reaches its Eastern stationary point and Mercury enters Leo.
At 0730 UT on July 22nd Mars (mag. +1.7), Venus (-4.3) and Mercury (-0.2) form a broad isosceles triangle in South-western Leo, with Venus at the apex. The angular distance between Mars-Venus and Venus-Mercury is 9°.7 and the distance from Mars to Mercury is 17°.2. By midnight UT on July 25th Venus is 11°.5 to the West of Mars, with Mercury 14°.6 to the WNW.
At 1230 UT on July 26th Venus and Mercury (-0.0) are in conjunction, Mercury passing 5°.3 to the North of Venus. At the moment of conjunction Mars is 12°.5 to the East of the pair. Much like Venus before it, Mercury's path against the stars begins to curve slightly Southwards from around this time.
At 0046 UT on July 29th Mercury passes 7' (0°.11) South of Regulus, with Mars positioned 11°.2 to the ESE. Venus is now 14°.6 to the West of Mars.
In the midnight hour (UT) of August 1st Mars, Mercury (+0.2) and Venus (-4.1) form an isosceles triangle beneath the Lion's belly, with Mercury at the apex. The angular distance between Mars-Mercury and Mercury-Venus is 9°.0 and that from Mars to Venus is 17°.3. Mercury crosses to the South of the ecliptic on the same day.
At 2040 UT on August 3rd Mars passes 29' (0°.48) South of Leo (Chi Leonis, mag. +4.6), a variable and double star, with Mercury 7°.3 to the West and Venus 20°.4 to the West.
Mars becomes lost from view from mid-Northern latitudes during the first week of August. In the closing weeks of the apparition, the three planets continue to shift their positions in relation to each after dusk. At midnight UT on August 5th Mercury (mag. +0.3) is 6°.7 to the West of Mars and Venus is 21°.5 to the West of it; at midnight UT on the 6th Mercury is 6°.2 to the West of Mars and Venus is 22°.7 to the West of it; at midnight on the 7th Mercury is 5°.8 to the West of Mars and Venus is 23°.8 to the West of it. Also on August 7th, Mars passes 9°.5 South of the star Chertan ( Leo or Theta Leonis, mag. +3.3), at the top of the Lion's rear leg. Prior to IAU standardisation in 2016 the star was also known as Coxa or Chort. At the same moment the planet passes 14°.5 South of the star Zosma ( Leo or Delta Leonis, mag. +2.7), at the rump of the Lion.
At midnight UT on August 8th Mercury is positioned 5°.6 to the West of Mars with a difficult Venus, caught in bright twilight, 25° to the West of the Red Planet. On the following day (10th) Venus' solar elongation falls below 10° and the planet effectively becomes lost from view in the solar glare, whilst Mercury (mag. +0.4) attains its greatest solar elongation (27°.4 East), positioned 5°.1 to the West of Mars. Also on the 10th, Mars passes 56' (0°.93) South of Leo (Sigma Leonis, mag. +4.0), which is positioned at the rear 'paw' of the Lion.
Mars and Mercury (mag. +0.5) come to within 4°.7 of each other on August 12th, but they do not reach conjunction. Mars passes 5°.7 South of Leo (Iota Leonis, mag. +4.0), positioned at the joint of the Lion's rear leg, on the same day.
Mars enters Virgo, the Maiden, at 22 hours UT on August 17th, with Mercury (mag. +0.8) having increased its angular distance to 5°.2 to the WSW of the Red Planet.
Mercury is 5°.5 to the WSW of Mars at midnight UT on August 19th, 5°.8 to the WSW of Mars at midnight UT on the 20th and 6°.1 to the WSW of the Red Planet at midnight UT on the 21st. Mercury (mag. +1.1) reaches its Eastern stationary point on August 22nd, positioned 6°.5 to the WSW of Mars.
Now only visible from South of the Northern Tropics, Mars passes just 1'.3 (0º.02) North of the star Zavijava ( Vir or Beta Virginis, mag. +3.6), at the back of the Maiden's head, at 1450 UT on August 23rd. Mercury is positioned 7°.3 to the WSW of Mars. Before IAU standardization Zavijava was also known by the names Zavijah, Zavyava or Alaraph.
On August 29th Mars crosses to the South of the celestial equator. Mercury heads out of view in the dusk twilight by month's end, leaving Mars as the only planet in the Western sky after sunset.
Mars passes 50' (0º.83) South of the star Zaniah ( Vir or Eta Virginis, mag. +3.8), in central Western Virgo, on September 5th. On September 14th the planet passes 2º.4 South of the double star Porrima ( Vir or Gamma Virginis, mag. +3.5), which prior to IAU standardisation in 2016 was sometimes known by the name of Arich. At this time of year the star is only visible from the Southern hemisphere for a brief period at dusk.
Mars' solar elongation falls below 20º East of the Sun in mid-September, by which time it becomes lost from view from the Northern Tropics. Only Equatorial and Southern hemisphere latitudes are now still able to view the planet. Mars is now slowly closing in on the Sun at a rate of 0º.3 per day, setting in the West between 1¼ hours (the Equator) and 1¾ hours (45º South) after the Sun. From the Southern hemisphere Mars stands just 10° above the Western horizon when it first becomes visible at dusk.
The ninth and final lunar occultation of the planet's apparition takes place on September 16th, when the waxing crescent Moon passes in front of Mars from around 18 hours UT. The event is visible in twilight from the central Atlantic Ocean and the Northern region of South America (Suriname, French Guiana and the Northern extreme of Brazil). For a map and timings of the event, follow the link provided in the Moon near Mars section below.
With its return to central Virgo, Mars has now completed a full circuit of the zodiac since passing through superior conjunction nearly two years earlier.
Mars passes 1º.4 to the South of Vir (Theta Virginis, mag. +4.4), in central Virgo, on September 25th. As the planet's solar elongation falls below 15° at month's end, it becomes lost from view from Equatorial latitudes. The Red Planet passes 2°.6 North of Virgo's brightest star Spica ( Vir or Alpha Virginis, mag. +1.0) on October 2nd. Mars becomes lost from view from the Southern hemisphere by the second week of October, bringing the planet's 2021-23 apparition to a close.
Mars reaches its most distant point from Earth (known as the apogee or, in the case of Mars, the apoareion) for this apparition on October 18th, when it lies at a distance of 2.5497 AU (381.4 million kms or 237 million miles). Were it to be visible from Earth at this time, its magnitude would be +1.6 and its apparent size only 3".6. Mars enters Libra, the Balance, on October 24th, crossing to the South of the ecliptic on November 6th.
Mars reaches superior conjunction (passing behind the Sun as viewed from the Earth) in South-eastern Libra on November 18th, when it is 2.5256 AU (377.8 million kms or 234.7 million miles) from Earth. The planet remains out of view - lost in the solar glare - for a further seven weeks as it continues its Eastward course on the far side of its orbit from the Earth. Mars becomes visible again in the Eastern sky at dawn from early January 2024, when it is first glimpsed from Equatorial latitudes. This heralds the start of the 2024-26 apparition, which will see Mars reach opposition in Gemini in January 2025.
[Terms in yellow italics are explained in greater detail in an associated article describing planetary movements in the night sky.]
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Mars Conjunctions with other Planets,
Viewed from the orbiting Earth, whenever two planets appear to pass each other in the night sky (a line-of-sight effect) the event is known as a planetary conjunction or appulse. Not all planetary conjunctions will be visible from the Earth, however, because many of them take place too close to the Sun. Furthermore, not all of them will be seen from across the world; the observers' latitude will affect the altitude (angle above the horizon) at which the two planets are seen at the time of the event, and the local season will affect the sky brightness at that particular time. A flat, unobstructed horizon will normally be required to observe most of them.
Alas, most conjunctions involving Mars are unspectacular to view because the planet is usually positioned far away from the Earth - and is therefore not particularly bright - whenever they take place. Those involving Venus will always take place at solar elongations of less than 47° from the Sun, whilst those involving Mercury will always take place at less than about 27° from the Sun. In both of these instances twilight is often a problem, the lighter sky diminishing the visual impact of the conjunction (Mars looking like an ordinary, pale-orange star). Without doubt, Mars' most spectacular conjunctions take place when it is within a few months of opposition - and therefore at its brightest - at which times they involve either Jupiter or Saturn; these events are however very rare. Most conjunctions between Mars and Jupiter (or Mars and Saturn) occur at elongations of less than 90°, when Mars is far from its brightest in any given apparition. The 2021-23 apparition has two relatively favourable conjunctions involving these two giant planets: a Saturn conjunction at an elongation of 53° and a Jupiter conjunction at 64°; they are both ideally placed for Southern hemisphere observers.
In the 2021-23 period there are six observable planetary conjunctions of Mars, involving five of the Solar System planets, all of which take place in the morning sky within 5½ months of 2022. Only one of them is particularly close, at less than 0°.5 separation. In all except one case their visibility favours Southern hemisphere observers. None of them are observable from higher Northern hemisphere latitudes, since nearly all take place at times when Mars has not yet come into view from these latitudes.
Perhaps the most interesting conjunction of the apparition is that between Mars and Jupiter on May 29th 2022. It takes place close to the celestial equator in central Southern Pisces, the Red Planet passing 38' (0°.63) to the South of the much brighter gas giant. It is ideally placed for Southern hemisphere observers. At magnitude -2.1, Jupiter shines thirteen times brighter than Mars and it consequently remains visible for a longer period of time in the dawn twilight. At latitude 50° North the two planets are placed just 16° above the ESE horizon as Mars disappears from view. At 30° North they are 37° above the ESE horizon at disappearance and at the Equator they are 58° above the Eastern horizon. Altitudes in the Southern hemisphere are a little better: 57° high in the North-east at latitude 25° South, 51° high in the NNE at 35° South and 43° high in the NNE at 45° South.
The closest conjunction of the apparition is that between Mars and Saturn on April 4th 2022, when Mars passes 19' (0°.31) to the South of the ringed planet in the tail of Capricornus. The conjunction is close not only in angular separation, but also in apparent brightness, their magnitudes differing by only 0.3 magnitudes. As the pair disappear from view in the dawn twilight Mars and Saturn are placed just 7° above the South-eastern horizon at latitude 50° North (from here they are seen in continuous twilight from rising through to disappearance). At 30° North they are 23° above the South-eastern horizon at disappearance and at the Equator they are 42° above the ESE horizon. In the Southern hemisphere the altitudes and directions are as follows: 48° high in the East at latitude 25° South, 47° high in the ENE at 35° South and 43° high in the ENE at 45° South.
Both conjunctions of Mars with Venus are widely separated - indeed, they are the widest of the six conjunctions. The March 12th 2022 conjunction is technically the better of the two, since it has a narrower separation (4°.0), greater horizon altitudes and Venus close to its maximum solar elongation. Venus, at magnitude -4.3, shines 158 times brighter than Mars. Venus can easily be seen in the dawn twilight but Mars disappears from view much sooner. At latitude 50° North the planets are positioned at 5° (Mars) and 9° (Venus) above the South-eastern horizon as Mars disappears from view; here the pair are seen in continuous twilight from rising to disappearance. At latitude 30° North they are positioned 20° (Mars) and 23° (Venus) high in the South-east as the Red Planet disappears. From the Southern hemisphere the altitudes and directions under the same circumstances are as follows: 41° high in the East at 25° South; 41° (Mars) and 39° (Venus) high in the East at 35° South and 38° (Mars) and 36° (Venus) high in the East at 45° South.
The February 14th 2022 conjunction between Mars and Venus takes place at the narrowest solar elongation (39° West) of the six events. The separation of 6°.5 - equivalent to the apparent width of thirteen Full Moons - is so wide that many might not consider it a conjunction at all! Venus, at magnitude -4.5, is shining at its brightest for its 2022 morning apparition. At latitude 50° North the planets are 7° high (Mars) and 13° high (Venus) over the South-eastern horizon at the Red Planet's disappearance; at 30° North the planets are 20° (Mars) and 25° (Venus) above the ESE horizon and at the Equator they are 33° (Mars) and 35° (Venus) above the ESE horizon. In the Southern hemisphere the altitudes and directions at disappearance are: 35° (Mars) and 33° (Venus) in the ESE at latitude 25° South, 33° (Mars) and 30° (Venus) in the East at 35° South and 30° (Mars) and 26° (Venus) in the East at 45° South.
The Mars and Uranus conjunction of August 1st 2022 takes place in Aries and is the only conjunction of the 2021-23 apparition which is more favourable for Northern hemisphere observers. Mars, at magnitude +0.2, shines brighter than at any of the other five planetary conjunctions of the period. As Uranus disappears from view in the twilight the two planets are positioned 26° in altitude towards the East at latitude 50° North, 41° high in the ESE at latitude 40° North, 58° high in the East at 20° North and 61° high in the North-east at the Equator. In the Southern hemisphere the altitudes and directions are as follows: 45° high in the NNE at 25° South, 36° high in the NNE at 35° South and 28° high in the NNE at 45° South. At the moment of conjunction Uranus is 17½ times further away than Mars and through telescopes it appears less than half the apparent disk size of the Red Planet.
In the conjunction between Mars and Neptune on May 17th 2022, the two planets are separated by 34' (0°.56) but they are positioned in different constellations: Mars in Aquarius and Neptune in Pisces. When Neptune disappears from view in the dawn twilight, the pair are placed just 7° high in the East at 40° North, 17° high in the ESE at 30° North and 38° high in the East at the Equator. In the Southern hemisphere they stand 43° high in the East when Neptune disappears from view at 15° South, 40° high in the ENE at 35° South and 36° high in the Norrh-east at 45° South. Telescopically Mars appears 2¾ times larger than Neptune and shines 692 times brighter! However any glare caused by the Red Planet's brightness when seen through a telescope is easily alleviated by the relatively wide separation between the pair.
The following table lists the observable conjunctions involving Mars during the 2021-23 apparition which take place at solar elongations of 15º or greater. Where other planets are also in the vicinity, details are given. Note that, because some of the conjunctions occur in twilight, the planets involved may not appear as bright as their listed magnitude suggests.
Mars conjunctions with other planets from February to August 2022 (click on thumbnail for full-size table, 37 KB). The column headed 'UT' is the Universal Time (equivalent to GMT) of the conjunction (in hrs : mins). The separation (column 'Sep') is the angular distance between the two planets, measured relative to Mars, e.g. on 2022 Mar 12, Venus is positioned 4°.0 North of Mars at the time shown. The 'Fav. Hem' column shows the Hemisphere in which the conjunction is best observed (Northern, Southern and/or Equatorial). Note that observers located close to the Northern/Southern visibility boundary of any given conjunction will find it difficult or impossible to observe because of low altitude and/or bright twilight..
In the 'When Visible' column, a distinction is made between Dawn/Morning visibility and Dusk/Evening visibility; the terms Dawn/Dusk refer specifically to the twilight period before sunrise/after sunset, whilst the terms Evening/Morning refer to the period after darkness falls/before twilight begins (some conjunctions take place in darkness, others do not, depending upon latitude). The 'Con' column shows the constellation in which the planets are positioned at the time of the conjunction.
To find the direction in which the conjunctions are seen on any of the dates in the table, note down the constellation in which the planets are located ('Con' column) on the required date and find the constellation's rising direction (for Dawn/Morning apparitions) or setting direction (for Dusk/Evening apparitions) for your particular latitude in the Rise-Set direction table.
A table of planetary conjunctions involving Mars from 2021 to 2025 can be seen here (89 KB).
Although any given conjunction takes place at a particular instant in time, it is worth pointing out that, because of the planets' relatively slow daily motions, such events are interesting to observe for several days both before and after the actual conjunction date.
There are in fact two methods of defining a planetary conjunction date: one is measured in Right Ascension (i.e. perpendicular to the celestial equator) and the other is measured along the ecliptic, which is inclined at 23½° to the Earth's equatorial plane (this is due to the tilt of the Earth's axis in space). An animation showing how conjunction dates are determined by each method can be found on the Jupiter-Uranus 2010-11 triple conjunction page. Although conjunction dates measured along the ecliptic can be significantly closer, the Right Ascension method is the more commonly used, and it is the one which is adopted here.
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Aries, Taurus & Gemini:
Aries & Western Taurus
Aries, Taurus, Gemini and Orion Photographs showing the region of the night sky through which Mars passes from mid-2022 to mid-2023 (click on the thumbnails for the full-size versions; 418 KB, 288 KB and 105 KB). The regions of the star chart which are visible in the photographs can be seen by clicking on the lower thumbnail (64 KB). For the Gemini photo, stars are visible down to about magnitude +6.5; for the Taurus photo, the limiting magnitude is about +8.0 and for the Aries photo it is about +7.5. Note that the photographs do not have the same scale because of the varying camera lens settings and image resolutions.
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Moon near Mars Dates,
December 2021 to September 2023
The Moon is easy to find, and on one or two days in each month, it passes Mars in the sky. The following tables list the dates on which the Moon passes near the planet during its 2021-23 apparition:
Moon near Mars dates for the period from December 2021 to September 2023 (click on thumbnail for full-size table, 69 KB). The Date Range shows the range of dates worldwide (allowing for Time Zone differences across East and West hemispheres). Note that the Date, Time and Separation of conjunction (i.e. when the two bodies are at the same Right Ascension) are measured from the Earth's centre (geocentric) and not from the Earth's surface. All times are Universal Time [UT], which is equivalent to GMT. The Sep. & Dir. column gives the angular distance (separation) and direction of the planet relative to the Moon, e.g. on April 25th 2022 at 22:05 UT, Mars is positioned 3°.9 North of the Moon's centre. The Moon Phase shows whether the Moon is waxing (between New Moon and Full Moon), waning (between Full Moon and New Moon), at crescent phase (less than half of the lunar disk illuminated) or gibbous phase (more than half but less than fully illuminated).
The Moon and Mars in Conjunction in September 2020, photographed by the writer (click on the thumbnail for the full-size image, 65 KB). The waning gibbous Moon passed 30' (0°.5) to the South of Mars in the dawn sky.
The Moon moves relatively quickly against the background stars in an Eastward direction, at about its own angular width (0º.5) each hour (about 12º.2 per day). Because it is relatively close to the Earth, an effect called parallax causes it to appear in a slightly different position (against the background stars) when seen from any two locations on the globe at any given instant; the further apart the locations, the greater the Moon's apparent displacement against the background stars. Therefore, for any given date and time listed in the table, the Moon will appear closer to Mars when seen from some locations than others. For this reason, the dates shown in the table should be used only for general guidance.
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Mars Meridian Transit Altitudes,
2012 to 2031
Mars is one of only two Solar System planets whose surface details can be seen through modest-sized telescopes (the other being Mercury, whose small size and low altitude often precludes a clear view). For the naked-eye observer, apart from the increased likelihood of obstruction from trees and buildings, a planet's low altitude is generally of little consequence. However for the telescopic observer, high altitude is essential in order to minimise the effects of turbulence, atmospheric dimming and light pollution (skyglow) which prevails near the horizon. Consequently, telescopic observers consider high altitude transits (when a celestial body crosses the observer's meridian, reaching its highest point in the sky) as more favourable than low altitude transits. As a general rule, telescopic observation is best done when a celestial body's altitude is greater than about 30°; hence observation in the couple of hours after rising or before setting is best avoided, unless there is no other alternative.
Mars' meridian transit altitude (as seen from any given point on Earth) varies as the planet drifts Eastwards through the zodiac from one opposition to the next. The altitude at which an observer sees a planet at meridian transit is determined not only by the constellation in which the planet is positioned at the time, but also by the observer's latitude. As a result, certain apparitions are more favourable to observers in one hemisphere than to observers in the opposite hemisphere.
In general, high-Northerly oppositions (in Taurus or Gemini) are best seen from the Northern hemisphere and high-Southerly oppositions (in Scorpius, Ophiuchus, Sagittarius or Capricornus) are best seen from the Southern hemisphere. Mars' last most Northerly opposition took place in Gemini in December 2007, when observers at mid-Northern latitudes saw the planet transit at around 60° to 70° high in the sky, providing optimal conditions for viewing through telescopes. Mid-Southern hemisphere observers fared rather worse, the planet transiting at around 20° to 30° high. After its 2007 opposition Mars began to descend the ecliptic, a process which continued through its next few oppositions in Leo (2012), Virgo (2014) and Scorpius (2016). After 2018 observing circumstances for Northern hemisphere observers have gradually improved as the planet ascends the zodiac once more, reaching opposition in Pisces (2020), Taurus (2022) and Gemini (2025).
Mars' last most Southerly opposition took place in Capricornus in July 2018, when observers at mid-Southern latitudes saw the planet transit at around 70° to 80° high in the sky; mid-Northern hemisphere observers saw it transit at just 20° to 30° high. Southern hemisphere observers, having experienced a few well-placed oppositions altitude-wise (in 2014, 2016 and 2018), will see observing circumstances worsen over the next few oppositions, the lowest altitudes being reached at the 2022 and 2025 oppositions.
Meridian Transit altitudes of Mars at successive oppositions from 2012 to 2031, as seen from a variety of latitudes (click on thumbnail for full-size table, 52 KB). The planet's best (brightest) oppositions take place when it is positioned in Aquarius, as it was in 2003. During these times Southern hemisphere observers benefit from a high transit altitude, much like the situation in 2018 (when the planet was in neighbouring Capricornus). Conversely, at these optimal times observers at high and mid-Northern latitudes must contend with less-than-ideal transit altitudes (< 35°). Meanwhile, the Martian disk as seen through the telescope began to shrink after the 2018 opposition and will only begin to increase from the 2029 opposition. Meridian transit altitudes for the period 2001 to 2010 can be seen here.
The varying transit altitude of Mars at each opposition is not the only factor which affects the ability to see the planet's surface details through telescopes; there is also the question of its hugely varying apparent size as seen from the Earth. This is the result of the planet's eccentric orbit, which brings it closer to the Earth at some oppositions than at others. For more details, see the Mars oppositions 2012-2027 page.
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Copyright Martin J Powell November 2021
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