The Venus Morning Apparition
by Martin J. Powell
The path of Venus through the zodiac constellations during the planet's morning apparition in 2018-19 (click on thumbnail for the full-size image, 47 KB). A version with constellation labels can be seen here (61 KB). Constellation names are shown in their three-letter abbreviated format - the full names are listed here. Zodiac constellations are labelled in green and non-zodiac constellations in grey. The numbers along the sides of the chart (Right Ascension and Declination) are co-ordinates of celestial longitude and latitude which are used to locate the position of a celestial body in the night sky. A print-friendly version is available here (21 KB).
Venus passes through inferior conjunction (when it is positioned between the Earth and the Sun) on October 26th 2018, positioned a significant 8º.3 South of the Sun's centre in the South-eastern region of the constellation of Virgo, the Virgin. The planet swiftly enters the dawn sky as a 'Morning Star' over the following week, visible in the twilight, low down over the ESE horizon less than 30 minutes before sunrise (the exact period depending upon the observer's latitude).
Orbitally, Venus is positioned at a relatively close 0.2724 Astronomical Units (AU) from the Earth (40.7 million kms or 25.3 million statute miles), a distance which will continually increase over the next eight months, through to the end of the apparition. The planet is moving retrograde (East to West) against the background stars at a rate of 0°.5 per day at this time, positioned to the South-east of Virgo's brightest star, Spica ( Vir or Alpha Virginis, mag. +1.0).
2 0 1 8 November
Venus reaches a solar elongation of 10º West on November 1st and 15º West on November 5th. The planet shines at an apparent magnitude of -4.2 at this time, brightening by a full half-magnitude over the next few weeks. Its apparent diameter (its angular width as seen from the Earth) is a sizeable 1' (i.e. 1 arcminute, where 1 arcminute = 1/60th of a degree). Venus' apparent diameter will slowly shrink over the course of the apparition, as it slowly recedes from the Earth in space.
As it pulls away from the Sun, telescopes pointed towards Venus show a large, slender, Eastward-facing crescent, rippling in the Earth's turbulent atmosphere (click here to see how Venus typically appears through a small telescope). In early November the planet's phase (i.e. the percentage of the disk which is illuminated) is only around 5% (phase = 0.05). The planet's large apparent diameter also means that the crescent can be glimpsed in the twilight by observers using binoculars, its apparently tiny crescent facing down towards the horizon.
Crescent Venus at 39% Phase imaged by Paul Maxson (Surprise, Arizona, USA) on July 28th 2012 using a 356 mm (14-inch) Schmidt-Cassegrain reflector telescope (click on the thumbnail for a larger image, 4 KB) (Image: Paul Maxson / ALPO).
At this early stage of the apparition, dedicated telescopic observers of Venus begin their search for the elusive Ashen Light, which is a faint glowing of the night side of Venus through its thick clouds. The phenomenon is believed to be caused either by the planet's surface glowing red hot (due to its extremely high surface temperature) or due to electrical activity in its dense atmosphere. Observers searching for the Light will normally use ultraviolet and/or infrared filters in order to help reveal it, an occulting bar often being used to block the bright, visually-intrusive crescent from view. Observers in Northern Tropical latitudes are best placed to view the Light at this stage of the apparition due to the planet's higher altitude (angle above the horizon) before sunrise.
By the second week of November Venus is rising in darkness across the inhabited world. The planet reaches its Western stationary point, 26º West of the Sun and 1º.2 East of Spica, on November 14th, moving slowly in a Northerly direction against the background stars. Venus crosses to the North of the ecliptic (the path of the Sun, which the Moon and planets follow very closely) on November 22nd.
On November 30th Venus attains its greatest brilliancy for this apparition at magnitude -4.7, positioned 5°.6 ENE of Spica. The planet's greatest brilliancy occurs when the percentage of the illuminated portion of the disk (phase) and its angular size combine to best visual effect. In the 2018-19 morning apparition this takes place when the planet is 25% illuminated (phase = 0.25), its angular diameter is 41".6 (41.6 arcseconds, where 1 arcsecond = 1/60th of an arcminute or 1/3600th of a degree) and its solar elongation is 39°. This is also the planet's brightest magnitude since 2010 (i.e. its maximum brightness), the reason being that Venus will pass perihelion (its closest orbital point to the Sun) less than one month from now, on December 26th.
On greatest brilliancy day Venus appears at a relatively good altitude above the horizon from across the inhabited world. From 60° North the planet reaches 18° above the SSE horizon at one half-hour before sunrise. At the same period before sunrise the planet attains 24° above the South-eastern horizon at 50° North, 30° above the South-eastern horizon at 30° North and 30° above the Eastern horizon from the Equator. Observers at mid-Southern hemisphere latitudes fare only slightly worse than Northern hemisphere observers, the planet being 17° above the Eastern horizon at 35° South and 11° above the Eastern horizon at 45° South.
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2 0 1 8 December
In early December Venus is joined in the dawn sky by the planet Mercury (mag. +0.8), now commencing its fourth morning apparition of 2018 and its seventh of the year overall (including evening apparitions). Owing to the relatively high angle of the ecliptic to the local Eastern horizon at dawn at this time of year, this particular apparition of Mercury favours Northern hemisphere observers. It is one of two paired apparitions between Venus and Mercury which take place during the 2018-19 apparition (a paired apparition being when the two planets are visible together for a prolonged period of time, either in the morning sky or the evening sky). The two planets come closest together on December 12th when Mercury (mag. -0.2) is positioned 23°.2 to the ESE of Venus. Mercury itself reaches greatest Western elongation (21°.2 West of the Sun) on December 15th. The waning crescent Moon passes near the two planets from December 4th to 6th and from January 1st to 3rd 2019.
Venus, Spica, Saturn and the Moon in the morning sky, sketched by Krzysztof Kida from Elblag, Poland on December 1st 2010 (click on the thumbnail for a larger image, 6 KB). A similar grouping (but without Saturn) will be seen just before dawn on December 2nd 2018. The full-size sketch can be seen at the Astronomy Sketch of the Day website.
Around this time, observers at higher Northern latitudes see Venus attain its highest altitude in the sky before sunrise for the 2018-19 apparition. At latitude 60° North, the planet rises some 4¾ hours ahead of the Sun, attaining an altitude of 19° above the SSE horizon at 30 minutes before sunrise. From these latitudes the 2018-19 apparition will be a short one - lasting only a few months - as low altitude and twilight begin to overwhelm Venus from around mid-February 2019.
Venus passes 0°.5 South of the star Kang ( Vir or Kappa Virginis, mag. +4.2) on December 12th. In Chinese astronomy Kang was both a constellation and a name given to the second lunar mansion. The name was formerly adopted in 2017 by the Working Group on Star Names (WGSN), a newly-established division of the International Astronomical Union (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. Venus passes by several other 'newly-named' stars during its 2018-19 morning apparition, each 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.
Around mid-December, observers at mid-Northern latitudes see Venus attain its highest altitude before sunrise for the 2018-19 apparition. At latitude 50º North the planet rises four hours ahead of the Sun, reaching an altitude of 25º in the SSE at 30 minutes before sunrise. At 40º North Venus rises 3¾ hours before the Sun, reaching 30º high in the South-east at 30 minutes before sunrise.
Venus enters Libra, the Balance (or Scales), on December 13th, passing 3°.0 North of the double-star Zubenelgenubi (2 Lib or Alpha2 Librae, mag. +2.8) on December 22nd and 11º.5 North of the star Brachium ( Lib or Sigma Librae, mag. +3.3) on December 26th. The planet passes 5º.2 South of the star Zubeneschamali ( Lib or Beta Librae, mag. +2.5), the Northernmost star of the Balance figure, on December 29th. The late astronomer Sir Patrick Moore once described Zubeneschamali as being 'the only naked-eye star which is said to have a greenish tint - though most observers will certainly class it as white!'.
2 0 1 9 January
Venus passes 57' (0º.95) South of the star Zubenelhakrabi ( Lib or Gamma Librae, mag. +4.0) on January 3rd, a name which was alternatively spelled Zuben Elakrab before IAU standardisation in 2017. It is commonly said to mean 'claw of the Scorpion' although it originates from a much earlier Sumerian name meaning 'balance of heaven'. The reference to the Scorpion derives from the fact that the ancient Greeks considered the stars in this region of the sky to be part of Scorpius, the Scorpion, before the Romans divided them into two separate constellations.
In early January, observers at Equatorial and Northern Tropical latitudes see Venus reach its highest altitude of the 2018-19 morning apparition. From the Equator the planet rises 3¼ hours ahead of the Sun, reaching an altitude of 39º in the ESE at 30 minutes before sunrise. From the Northern Tropics Venus rises 3½ hours before the Sun, reaching 34º in altitude at 30 minutes before sunrise. In fact, when assessed in terms of the planet's horizon altitude and visibility duration before sunrise, the 2018-19 morning apparition of Venus is best seen overall from Equatorial latitudes.
Venus reaches its greatest elongation (46°.9 West of the Sun) at 0444 UT on January 6th, positioned 3°.4 ESE of Zubenelhakrabi and 1°.4 WNW of the star Lib (Theta Librae, mag. +4.1). Although the planet's greatest elongation from the Sun takes place on January 6th, Venus is in fact positioned at an elongation of 46°.9 for a 10-day period from January 1st through to January 11th. Telescopes now show Venus' disk half-illuminated (phase = 0.50 or 50%), which is often referred to as the moment of dichotomy. The planet now has an apparent diameter of 25".0 and it shines at magnitude -4.4. When seen from a point far above the Solar System, the Earth, Venus and the Sun would now form a right-angled triangle in space, with Venus positioned at the 90° angle.
For a few days around greatest elongation, telescopic observers often attempt to determine the precise moment when the terminator (the line separating the light and dark sides of the planet) appears perfectly straight, essentially dividing Venus into two perfect halves. Solar System geometry suggests that this should occur on greatest elongation day, however it often does not and the precise reason for this was not understood until quite recently. Observers often report the straight terminator a few days earlier or later than the greatest elongation date (early in evening apparitions and late in morning apparitions). Hence in the current apparition, telescopic observers can expect to see a 50% phase on or around January 8th. This is commonly known as the phase anomaly or Schröter's Effect (after the German astronomer Johann Schröter, who first observed the phenomenon in 1793). It is thought to be due to Venus' dense atmosphere scattering the sunlight.
Venus at Dichotomy sketched by Detlev Niechoy (Göttingen, Germany) on March 28th 2014 using a 101 mm (4-inch) refractor telescope at 65x magnification (click on the thumbnail for a larger image, 14 KB) (Image: Detlev Niechoy / ALPO).
Contrary to what one might think, greatest elongation day is not necessarily the day on which Venus is above the horizon ahead of sunrise for the longest period of time. Since the angle of the ecliptic to the Eastern horizon at dawn varies with the observer's latitude, Venus is above the horizon for differing periods of time at different latitudes. At 60° North Venus rises 4 hours before sunrise, whilst at 45° South the planet rises 2¾ hours before the Sun. At other latitudes the visibility durations are as follows: 3¾ hours at 50° North; 3½ hours at 30° North; 3¼ hours at the Equator and 3 hours at 35° South. Hence for the current apparition, observers at higher Northern latitudes are best placed to see Venus above the horizon for the longest period on greatest elongation day.
Greatest elongation day now having passed, the phase of Venus changes from crescentic to gibbous, as it will remain through to the end of the apparition.
Venus passes just 2'.7 (0º.04) - only 6½ apparent Venus diameters - South of the aforementioned star Lib at around 1430 UT on January 7th. In the early hours (UT) of January 8th the planet passes 5º.6 North of the star Dschubba ( Sco or Delta Scorpii, mag. +2.2), which is located in the neighbouring constellation of Scorpius, the Scorpion. Later that same day Venus passes 9º.1 North of the star Fang ( Sco or Pi Scorpii, mag. +2.8), also in Scorpius, specifically in the head of the Scorpion. The name was formally assigned to the star by the IAU in 2017 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".
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Venus enters Scorpius on January 9th, passing 2°.4 North of the striking double-star Acrab (1 Sco or Beta-1 Scorpii, combined mag. +2.6) at around 0845 UT on the following day. Before IAU standardisation in 2016 the star was alternatively called Graffias, a name which is thought to refer to a crab's claws and is therefore, synonymous with those of a scorpion. The star's two blue-white components (1 Sco and 2 Sco) are magnitudes +2.6 and +4.9 respectively, 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.
Later on the same day (January 10th), between the hours of 1630 UT and 1945 UT, Venus passes 3º.3 North of the two Omegan stars Jabhat al Akrab (1 Sco or Omega-1 Scorpii, mag. +3.9) and Omega-2 Scorpii (2 Sco, mag. +4.3). Together with Dschubba, Acrab and the quadruple star named Jabbah ( Sco or Nu Scorpii, mag. +4.0), they form a distinctive asterism (star pattern) in Northern Scorpius. Venus passes 1º.8 North of Jabbah on the following day (11th).
On January 12th at around 02 hours UT the distance between the Earth and Venus is the same as that between the Sun and Venus, at 0.7189 AU (107.5 million kms or 66.8 million miles). Seen from far above the Earth's North pole, the Earth, Venus and the Sun now appear to form an isoscelene triangle in space, with Venus positioned at the apex.
Five stars in Scorpius were formally assigned new names by the International Astronomical Union in 2017. In this map of the constellation they are labelled in dark yellow (click on the thumbnail for the full-size image, 41 KB).
At around 2350 UT on January 13th Venus passes 7º.4 North of the variable star named Alniyat ( Sco or Sigma Scorpii, mag. +2.9v). At 11 hours UT on January 14th, the planet leaves Scorpius and enters the non-zodiacal constellation of Ophiuchus, the Serpent-Bearer. Later that same day (2055 UT) Venus passes 8º.0 North of Scorpius' brightest star Antares ( Sco or Alpha Scorpii, mag. +1.0v), which shines with an unmistakable orange-red hue. At 2214 UT on January 15th Venus comes to within just 22" (0'.36 or 0º.006) of the Ophiuchan boundary with Scorpius, the planet passing fractionally North of a 1º.5 by 1º rectangular section of sky which projects Eastwards from Northern Scorpius into South-western Ophiuchus.
Venus has been slowly approaching the giant planet Jupiter to its ESE since the gas giant's emergence into the dawn sky in mid-December 2018. Now in the early stage of its 2019 apparition, Jupiter (currently mag. -1.7) has spent the past year in Libra and moved into Scorpius in November 2018. The planet is positioned 7°.2 to the ESE of Venus on January 15th, 5°.6 South-east of Venus on January 17th and 4°.1 South-east of it on the 19th.
Over the following two weeks Venus passes to the North of four stars which were formally assigned 'new' names by the IAU in 2017. All four are located in the tail of Scorpius and none of them can be seen from latitudes North of 55° North since they never rise above the horizon from these latitudes. On January 20th Venus passes 14º.9 North of the star Larawag ( Sco or Epsilon Scorpii, mag. +2.2), positioned about half-way along the Scorpion's tail, which is an Aboriginal name from the Wardaman culture of Northern Australia. The other Aboriginal names assigned by the IAU to stars in the night sky are Ginan and Wurren (both from Wardaman culture) and Unurgunite (from the Boorong culture of South-eastern Australia); these apply to the stars Epsilon Crucis, Zeta Pheonicis and Sigma Canis Majoris, respectively.
On January 21st Venus passes 18º.7 North of the stars Xamidimura (1 Sco or Mu-1 Scorpii, mag. +2.9) and Pipirima (2 Sco or Mu-2 Scorpii, mag. +3.5), which are located 3º.5 South of Larawag. 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 to each other. 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.
By January 21st the apparent distance between Venus and Jupiter in the night sky has reduced to just 2°.8. On January 22nd Venus (mag. -4.2) passes 2°.4 North of Jupiter (-1.7) in an event called a planetary conjunction. These take place when two planets attain the same celestial longitude, so that they appear close together in the night sky. This particular conjunction, although having a rather wide separation, is well-placed for viewing across the inhabited world. Telescopically Venus is slightly gibbous (60% illuminated) and appears about two-thirds of the apparent size of Jupiter. In the current morning apparition of Venus there will be four observable planetary conjunctions involving the planet (with each of the four outermost planets of the Solar System), of varying viewing difficulty. For more details, see the planetary conjunctions section below.
Venus passes 4°.2 South of Sabik ( Oph or Eta Ophiuchi, mag. +2.5), the second brightest star in Ophiuchus, on January 24th. Sabik appears at the South-western corner of a trapezoidal arrangement of stars which the uninitiated might assume are all part of the same constellation. In fact, only Sabik is located in Ophiuchus; the other three stars are located in the constellation of Serpens Cauda, the Serpent's Tail. They are, namely, Ser (Xi Serpentis, mag. +3.5), Ser (Omicron Serpentis, mag. +4.2) and Ser (Nu Serpentis, mag. +4.3). Venus passes 4°.7 North of Theta Ophiuchi ( Oph, mag. +3.2), the brightest star in the Southernmost region of Ophiuchus, on January 27th.
At around 1737 UT on January 31st, observers located in the Central and Eastern Pacific Ocean and in North-western South America are able to observe the waning crescent Moon passing in front of Venus, blocking it from view, in an event known as a lunar occultation. The event takes place in darkness and/or twilight in the Central Pacific but in daylight further East along the track of visibility. Given that Venus is easily seen in daylight with optical aid, and that the planet is positioned a wide 45° West of the Sun at the moment of occultation, then observers who are in daylight can also witness this event. Details of the timings and track of visibility can be seen by following the link in the Moon near Venus Dates section below.
Less than an hour after the lunar occultation takes place, Venus leaves Ophiuchus and enters the constellation of Sagittarius, the Archer.
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2 0 1 9 February
On February 2nd Venus passes 18º.1 North of the fourth star in Scorpius' tail to be assigned a 'new' formal name by the IAU in 2017. The star is Fuyue (G Scorpii, mag. +3.2), positioned at the tail-end ('sting') 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.
In early February, observers at Southern Tropical latitudes see Venus reach its highest altitude of the 2018-19 apparition. From 25º South the planet rises 3¼ hours ahead of the Sun, reaching an altitude of 35º in the East at 30 minutes before sunrise. Elsewhere the planet is rising 2 hours before the Sun at 60º North, 2¾ hours before the Sun at 40º North, three hours before sunrise at the Equator and 3¼ hours before sunrise at 35º South. The altitudes and directions attained by the planet from these latitudes at one half-hour before sunrise are: 6º high in the SSE at 60º North, 19º high in the South-east at 40º North, 35º high in the ESE at the Equator and 33º high in the East at 35º South.
For a period of 19 hours between February 4th and 5th, Venus passes 3º.3 North of the sixth-magnitude gaseous nebula commonly called the Lagoon Nebula or Messier 8 (NGC 6523). With an apparent dimension of 90' by 40', the nebula is visible to the naked-eye from dark sites and is a spectacular sight through larger telescopes - particularly those fitted with nebular filters.
Over the course of the next twelve days, Venus passes several degrees North of Sagittarius' famous asterism, the Teapot, which comprises eight stars of third-magnitude or brighter. Taken counter-clockwise, they are: Alnasl, Kaus Media, Kaus Borealis, Phi Sagittarii, Nunki, Tau Sagittarii, Ascella and Kaus Australis. Early star guides often identified a different asterism here: the Milk Dipper, which comprised the Teapot's 'handle' stars together with Kaus Borealis and the star Polis ( Sgr or Mu Sagittarii, mag. +3.8v), just to the North-west of the Teapot. The Milk Dipper was envisaged as a ladle dipping into the rich Milky Way, though it seems to have fallen out of recognition in recent decades.
On February 5th Venus passes 9º.3 North of the star Alnasl ( Sgr or Gamma Sagittarii, mag. +3.0), positioned at the front of the Archer's bow. Prior to IAU standardisation in 2016 it was variously known by the names Nash or Alnasr, among others. On February 6th the planet passes just 5'.9 (0º.09) South of the aforementioned star Polis. It is an eclipsing binary star with a tiny brightness variation of ±0.1 magnitudes.
On February 8th Venus passes 8º.7 North of the star Kaus Media ( Sgr or Delta Sagittarii, mag. +2.7), positioned at the centre of the Archer's bow. Before IAU standardisation in 2016 it was also known by the names Kaus Meridionalis and Kaus Medius. On February 9th the planet passes 13º.2 North of Sagittarius' brightest star Kaus Australis ( Sgr or Epsilon Sagittarii, mag. +1.8). Given that it was desgnated the Greek letter epsilon, one might expect Kaus Australis to be the fifth-brightest star in the constellation. However, it is only one of many examples in the night sky where the brightest star in the constellation was not assigned the correct letter - namely, alpha (). Later on the same day (February 9th) the planet passes 4º.2 North of the star Kaus Borealis ( Sgr or Lambda Sagittarii, mag. +2.8) which marks the top of the Teapot asterism (and the top of the Archer's bow). The name Kaus is Arabic for 'bow', its Northern and Southern sections (Borealis and Australis) being later Latin additions.
Brilliant Venus rising in darkness in the morning sky, photographed by the writer in August 2017 (click on the thumbnail for the full-size picture, 88 KB).
Venus attains its most Southerly declination for this apparition, at -21° 12' (-21°.2 in decimal format) on February 10th. Across the inhabited world the planet now rises at its most Southerly position on the local horizon. This would typically be towards the South-east at latitudes far away from the Equator and towards the ESE at Equatorial latitudes.
On February 11th the planet passes 2º.7 North of the 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 beautifully resolved in telescopes.
Over the next week Venus passes North of the four stars which form the 'handle' of the Teapot. The planet passes 5°.8 North of Phi Sagittarii ( Sgr, mag. +3.1) on February 13th and 5°.2 North of the constellation's second-brightest star Nunki ( Sgr or Sigma Sagittarii, mag. +2.0) on February 15th. At 1957 UT on the same day, and away from the Teapot, the planet passes just 2' (0°.03) - only seven apparent Venus diameters - North of the star 2 Sgr (Xi-2 Sagittarii, mag. +3.5), which marks the forehead of the Archer figure. Venus passes 8°.9 North of Ascella ( Sgr or Zeta Sagittarii, mag. +2.6), at the base of the Teapot's handle, on February 16th. At 0530 UT on the following day (17th) the planet passes 0°.7 North of the star Sgr (Omicron Sagittarii, mag. +3.7) which marks the eye of the Archer. Finally, later that same day, Venus passes 6°.7 North of Sgr (Tau Sagittarii, mag. +3.3) which marks the Eastern end of the Teapot.
By mid-February Venus has faded slightly further to magnitude -4.1 and its phase has increased to 70%, so that its appearance through telescopes is now noticeably gibbous. At 0548 UT on February 18th Venus passes just 6'.2 (0°.1) North of the star Albaldah ( Sgr or Pi Sagittarii, mag. +2.9), positioned at the top of the Archer's head. Venus will occult (pass in front of) Albaldah during its morning apparition in February 2035, two Venus cycles hence (see the accompanying article describing The Venus 8-year Cycle). Eight hours later, Venus has its second planetary conjunction of the current apparition when it passes 1°.1 North of the planet Saturn (mag. +0.6). For observers at mid-Northern latitudes, this is the last visible conjunction of the 2018-19 morning apparition. Saturn is in the early stage of its 2019 apparition, having emerged into the dawn sky in mid-January. Its splendid rings are nicely displayed at the present time, being tipped at close to their maximum angle towards the Earth. Saturn will be seen at its best in July, when it reaches its closest point to the Earth at a relative position in its orbit known as opposition.
Around mid-February, observers at mid-Southern latitudes see Venus attain its highest altitude of the 2018-19 morning apparition. From latitude 35º South the planet rises 3¼ hours ahead of the Sun, reaching 33º high (one-third of the way 'up the sky') in the East at 30 minutes before sunrise. From latitude 45º South, the planet reaches its highest point in the sky before sunrise about two weeks later.
On February 19th at around 0040 UT Venus 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). The distance between Venus and the Earth is increasing daily at an average rate of about 1.066 million kms (662,600 statute miles) at this point in the apparition.
Having now passed the brighter stars of the Archer, Venus continues its way though the much fainter, Eastern region of the constellation over the next five days. The planet passes 4°.5 to the North of the star 52 Sagittarii (mag. +4.6) on February 23rd, then on the 27th it passes 6°.5 North of the star named Terebellum ( Sgr or Omega Sagittarii, mag. +4.7). The Latin name derives from an original Greek word meaning 'quadrilateral', since it is one of a group of four 4th-magnitude stars positioned within 2° of each other in the 'rump' of the Archer figure. The Terebellum were named by Claudius Ptolemy (ca. 100-170 AD) in his famous star catalogue, the Almagest. The other three stars in the group are 59 Sgr (mag. +4.7), 60 Sgr (mag. +4.8) and 62 Sgr (mag. +4.5).
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2 0 1 9 March
Venus leaves Sagittarius behind it and enters Capricornus, the Sea Goat, on March 1st, passing 6°.5 South of the star Prima Giedi (1 Cap, or Alpha-1 Capricorni, mag. +4.2) on March 3rd. Just over an hour later the planet passes 6°.4 South of the star Algedi (2 Cap or Alpha-2 Capricorni, mag. +3.6) which, prior to IAU standardisation in 2016, was also known as Secunda Giedi. Prima Giedi and Algedi are separated in the night sky by 6'.4 (0°.1) and are an easy optical double, meaning that they appear to the naked-eye as a double star but they are not physically related (in this case being 700 light years and 108 light years distant, respectively). Through a telescope, the pair are both seen to be double, Prima Giedi having a 9th-magnitude companion (also an optical double) and Algedi having a genuine binary companion of 11th-magnitude. Larger telescopes reveal that this 11th-magnitude star is itself double.
At high and mid-Northern latitudes the shallow angle of the ecliptic to the local horizon at dawn now means that Venus does not attain any great altitude before sunrise takes place. In early March, observers at higher Northern latitudes lose sight of Venus altogether as it sinks into the lengthening dawn twilight. Here the planet will not become visible again until it appears in the evening sky in December. At latitude 50° North Venus rises 1½ hours before the Sun but only reaches an altitude of 6° in the South-east at 30 minutes before sunrise. Elsewhere the planet rises two hours before sunrise (at 30º North), 2½ hours before sunrise (at the Equator) and three hours before the Sun (at 35º South). At thirty minutes before sunrise, Venus stands 17º high in the South-east at 30º North, 29º high in the ESE at the Equator and 31º high in the East at 35º South.
By March 4th the solar elongation of Venus has reduced to 40º West and its apparent diameter has reduced to 15" - only one-quarter of the size it had been at the start of the planet's apparition. On the same day the planet passes 4º.0 South of the variable and multiple star Dabih (1 Cap or Beta-1 Capricorni, mag. +3.0v). The name is Arabic for 'lucky one of the slaughterers', a reference to the historical sacrifice of animals (often goats) by heathen Arabs, who once performed the sacrifice at the rising of Capricornus. The planet passes 0º.6 North of the star Cap (Theta Capricorni, mag. +4.0), at the centre of the Sea Goat's body, on March 13th. Venus crosses the ecliptic Southwards on March 14th, then on March 17th passes 1º.2 North of the star Cap (Iota Capricorni, mag. +4.3).
Several degrees to the North of Venus is the Western half of the constellation of Aquarius, the Water Carrier. 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. Some 2º.7 to the South-east of Sadalsuud 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. Venus passes 9º.3 South of Sadalsuud on March 19th and 6º.6 South of Bunda on March 20th. Later on the 20th - and back in Capricornus - the planet passes 2º.3 North of the star Nashira ( Cap or Gamma Capricorni, mag. +3.7), located in the tail of the Sea Goat. Finally, on March 22nd, Venus passes 2º.3 North of the constellation's brightest star, a variable named Deneb Algedi ( Cap or Delta Capricorni, mag. +2.9v). The name means 'tail of the goat' and it was also known as Deneb Algiedi or Scheddi before IAU standardisation in 2017.
From around the third week of March, Venus, now magnitude -4.0, is again joined in the dawn sky by the planet Mercury (mag. +2.5) in the second paired apparition between the two planets during Venus' 2018-19 morning apparition. Unlike Mercury's previous morning apparition in December 2018, this one favours Southern hemisphere observers. The two planets will come closest together in mid-April.
Venus enters Aquarius on March 24th, passing 12º.0 South of the constellation's second-brightest star Sadalmelik ( Aqr or Alpha Aquarii, mag. +2.9) on March 26th. Although incorrectly assigned the Greek letter alpha - intended for the brightest star in the constellation - the brightness difference between this star and the constellation's true brightest star (Sadalsuud or Aqr) is fractional: Sadalmelik has an apparent visual magnitude of +2.95 whilst that of Sadalsuud is +2.90. Given the difference of just 0.05 magnitudes, we can perhaps forgive Johann Bayer, who first allotted stars their Greek letters in his 1603 star catalogue - and who had to estimate their order of brightness by naked-eye!
Later on March 26th Venus passes 1º.5 North of the star Aqr (Iota Aquarii, mag. +4.2), positioned at the 'knee-joint' of the Water Carrier's advancing leg. Two days later (28th) the planet passes 3º.7 South of the star Ancha ( Aqr or Theta Aquarii, mag. +4.1). Between March 29th and April 1st the planet is positioned about 10º South of Aquarius' best-known identifier, the so-called 'Steering Wheel' asterism. 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 spread across the zodiac with which beginner astronomers should become familiar, in order to aid constellation identification.
At 15 hours UT on March 31st Venus passes 22' (0º.36) North of the star Aqr (Sigma Aquarii, mag. +4.8), which is positioned more or less at the centre of Aquarius. Venus will occult Aqr during its morning apparition of 2048.
2 0 1 9 April
On April 5th Venus passes 0º.7 South of the star Aqr (Lambda Aquarii, mag. +3.9), which the planet occulted during its 2014 morning apparition. The planet passes 7º.7 North of the star Skat ( Aqr, or Delta Aquarii, mag. +3.2), at the base of the Waterman's amphora, later that same day.
At 0346 UT on April 10th Venus (mag. -3.9) passes just 18' (0º.3) South of the planet Neptune (+7.9) in the third planetary conjunction of the 2018-19 apparition. The conjunction is visible only from latitudes which are South of the Northern Tropics. Owing to the large brightness difference between the two planets it is a difficult conjunction to observe and in any case optical aid is required in order to see Neptune. There is some added interest in that the star Aqr (Phi Aquarii, mag. +4.2) is positioned between the two planets, some 5'.2 (0º.08) to the SSE of Neptune. Venus passes 13' (0º.2) to the South of Aqr itself only 36 minutes later, at 0422 UT. Neptune, Aqr and Venus form a line 17' (0º.28) in length at 0542 UT, visible in darkness from North-western Africa.
Between April 10th and 16th Venus passes several degrees South of the Circlet of Pisces, positioned at the Western end of Pisces, the Fishes. The Circlet is the most distinct feature of the constellation and comprises six stars of fourth and fifth magnitude. At this time of year the Circlet is only visible South of mid-Northern latitudes, and only for a short period of time after rising.
Mercury, now magnitude +0.5, reaches its greatest elongation (27°.7 West of the Sun) on April 11th, positioned 4°.9 to the ENE of Venus. Mercury comes to within 4°.6 of Venus on April 12th, following which the two planets move almost in unison over the next two weeks, Mercury being to the ENE of Venus throughout the period. Mercury enters Pisces along its South-western border on April 15th, followed by Venus the next day. They come to within 4°.2 of each other on April 17th but, as in the previous pairing in December 2018/January 2019, they do not reach conjunction. The waning crescent Moon passes near the two planets from April 1st to 3rd and from May 2nd to 4th.
As Venus' solar elongation narrows to 30° West on April 20th, the planet passes 8º.6 South of the star Psc (Omega Piscium, mag. +4.0), which is located a short distance East of the Southern Fish's head. It is also the brightest star which is positioned closest to the 'zero-hour' of celestial longitude, being just 0'.69 (0°.011) West of 0 hours Right Ascension (epoch 2000.0 coordinates). At this time of year only observers South of about latitude 35° North are able to view it.
Mercury, having brightened to magnitude +0.1, begins to pull away Eastwards from Venus after April 20th. Mercury leaves Pisces and enters the constellation of Cetus, the Whale, on April 22nd, clipping the North-western corner of that constellation. Venus crosses from South to North of the celestial equator (declination = 0°) on April 23rd, positioned 3°.8 East of the Sun's Vernal Equinox position (known historically as the First Point of Aries) where celestial longitude measurement originates (ecliptic longitude = 0° and Right Ascension = 0h 0m 0s). The planet now rises just 45 minutes before sunrise at 50° North, 1¼ hours before sunrise at 30° North, 1¾ hours before the Sun at Equatorial latitudes and 2¼ hours before the Sun at mid-Southern latitudes. Being positioned so close to the celestial equator at this time, the planet now rises due East across the inhabited world.
Venus enters Cetus on April 26th and later that same day Mercury (mag. -0.0) re-enters Pisces through its central Southern boundary. Venus itself re-enters Pisces in the same vicinity on April 29th.
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2 0 1 9 May
During the first week of May Mercury heads back in towards the Sun and is lost from view thereafter. On May 1st Venus passes 4º.1 South of the star Psc (Delta Piscium, mag. +4.4), positioned about half-way along the Southern Fish's body, and then 2º.9 South of the star Psc (Epsilon Piscium, mag. +4.3) on May 4th. At this time of year the faint stars of Pisces, rising in the East at dawn, are only visible from latitudes which are South of the Northern Tropics.
On May 6th Venus passes 1°.5 South of the double star Revati ( Psc or Zeta Piscium,, mag. +5.2), a name adopted by the IAU in 2017 and which is derived from the ancient Hindu lunar mansions. She was the daughter of King Kakudmi in Hindu mythology and a consort of the god Balarama (the elder brother of Krishna).
Venus passes 7°.5 South of the star Alpherg ( Psc, or Eta Piscium, mag. +3.8), the brightest star in Pisces, on May 10th. The name, which is Arabic for 'the cord', rarely appears on star charts and is not in common usage. Alpherg is a yellow giant star which, to most amateur astronomers, serves as a 'finder star' for the galaxy M74 (NGC 628), a 10th-magnitude face-on spiral which is one of the faintest objects in the Messier catalogue. It is positioned just 1°.3 to the ENE of Alpherg.
The lengthening Northern hemisphere summer twilight means that the stars of Pisces are now only observable from Equatorial and Southern hemisphere latitudes. At 1814 UT on May 13th, Venus passes a mere 37" (0'.62 or 0°.01) South of the star Torcular ( Psc or Omicron Piscium, mag. +4.2), positioned in the tail of the Northern Fish. The separation equates to a little over three apparent Venus widths. The name Torcular was formerly standardized by the IAU in 2017, the original name having been the fanciful Torcularis Septentrionalis. Venus will occult the star on the same calendar date in 2027, during the planet's morning apparition.
Venus enters the constellation of Aries, the Ram, on May 16th, passing 8°.0 North of the double-star Alrescha ( Psc or Alpha Piscium, mag. +3.8), in neighbouring Pisces, on May 17th. The name was standardized by the IAU in 2016, the star having previously been 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.
At 0813 UT on May 18th Venus passes 1°.1 South of the planet Uranus (mag. +5.9) in the final planetary conjunction of the 2018-19 morning apparition. Uranus re-entered Aries from Pisces in the previous February, having spent almost nine years in the latter constellation. This conjunction can only be viewed South of the Northern Tropics. Telescopically Venus is now only a little over 10" wide and shows a gibbous phase of over 90%, so that it is difficult to differentiate it from a fully-illuminated disk (Uranus appears only as a tiny, 3".4 wide blue-green disk). Later on May 18th, Venus passes a wide 12°.2 South of Aries' brightest star Hamal ( Ari or Alpha Arietis, mag. +0.2), which was found to have an extra-solar planet or exoplanet (a planet outside our own Solar System) in 2011.
From mid-Northern latitudes the visibility of Venus has been difficult for several weeks, the planet rising in twilight since late March and barely reaching any significant altitude before sunrise. As Venus heads Northwards along the ecliptic its visibility begins to improve very slightly from these latitudes, as the angle of the ecliptic to the local horizon at dawn steepens day by day. At latitude 50º North in late May, at 30 minutes before sunrise, the planet is positioned just 2° above the ENE horizon - but this is 1° higher in the sky than it was over the previous month. However, Venus' apparent motion towards the Sun counterbalances this apparent rise in altitude, so the effect will only last about a month. At latitudes further South the altitudes above the local horizon are steadily falling. At latitude 30º North some 30 minutes before sunrise, Venus is positioned 6º above the ENE horizon, being visible for 30 minutes thereafter. At the Equator, the planet rises 1¼ hours ahead of the Sun, reaching 11º above the ENE horizon at 30 minutes before sunrise. At 35º South the planet rises 1¾ hours before the Sun, reaching 12º above the ENE horizon at 30 minutes before sunrise.
On May 27th Venus passes 12º.2 South of the star Bharani (41 Ari or 41 Arietis, mag. +3.6), a name adopted by the IAU in 2017 after the second lunar mansion in Hindu astrology.
2 0 1 9 June
By early June Venus' solar elongation has reduced below 20° West and the planet is rising in twilight across the Northern hemisphere. Observers in the Southern hemisphere can now only observe stars in Aries and neighbouring Taurus, the Bull, which are brighter than about magnitude +4.0. Stars down to about +4.3 can still be glimpsed from the Equator and the Southern Tropics. One such example of the latter is the star Botein ( Ari or Delta Arietis, mag. +4.3), the Ram's Easternmost bright star, which Venus passes 3º.1 South of on June 1st.
The planet enters Taurus on June 3rd, passing 8º.5 North of the star Tau (Omicron Tauri, mag. +3.6), at the Western edge of the constellation, later that same day. Venus passes 4º.9 North of the star 5 Tau (5 Tauri, mag. +4.1) on June 5th.
Between June 7th and 8th Venus passes ca. 5° South of the open star cluster known as the Pleiades (pronounced 'PLY-add-eez' or 'PLEE-add-eez') or The Seven Sisters (M45), perhaps the best-known star cluster in the night sky. The cluster is neither seen well nor widely at this time of year, with only Equatorial and Southern Tropical latitudes being able to glimpse it, a few degrees above the ENE horizon just before dawn. Under dark skies the seven brightest stars in the group can be seen with the naked-eye and are often considered to be a good test of visual acuity. The planet takes about 21 hours to traverse the 1° angular distance between the cluster's brightest Western star (Electra) and its brightest Eastern star (Atlas).
On June 10th Venus passes 7°.2 North of the eclipsing binary star Tau (Lambda Tauri), positioned at the 'heart' of the Bull figure, whose magnitude varies from ca. 3.5 to 4.0 over a period of four days.
Between June 14th and 17th Venus passes several degrees North of another, much larger star cluster known as the Hyades, a distinct 'V'-shaped grouping of stars forming the head of the Bull. The cluster comprises around 400 stars spread over an area of about 5° of the sky. At the apex of the 'V' is the star Prima Hyadum ( Tau or Gamma Tauri, mag. +3.6) which, before standardization by the IAU, was known variously as Primus Hyadum or Hyadum I. Venus passes 5°.0 North of the star on June 14th. On June 15th Venus passes 3°.3 North of the star 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 Hyades cluster. Before IAU standardization in 2017, the star was also known as Secundus Hyadum or Hyadum II.
Also positioned along the Northern arm is the star Ain ( Tau or Epsilon Tauri, mag. +3.5), marking the base of the Bull's Northern horn. An exoplanet was detected orbiting this star in 2007. Venus passes 1°.3 North of the star on June 16th. At the same moment, Venus passes 5°.2 North of Chamukuy (2 Tau or Theta-2 Tauri, mag. +3.7), the brightest of the Hyades' 'true' members, 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 June 2017. The star forms a naked-eye yellow-white double with 1 Tau (Theta-1 Tauri, mag. +3.8), positioned some 337" (5'.6 or 0°.09) to the North.
Occupying the South-eastern corner of the Hyades cluster is the orange-red star Aldebaran ( Tau or Alpha Tauri, mag. +0.9), marking the 'eye' of the Bull. Its coloration derives from the fact that it is a red giant star. Most of the Hyades stars comprise a genuine cluster, moving through space together, however Aldebaran is not part of the group; it is a foreground star, positioned at a much closer distance of 68 light years. Venus passes 4°.8 North of Aldebaran on June 17th.
Venus' solar elongation reduces to 15° West of the Sun on June 19th.
2 0 1 9 July
On July 3rd Venus leaves Taurus and enters Gemini, the Twins, crossing the ecliptic in a Northward direction on July 5th. At 05 hours UT on July 7th Venus attains its highest declination for this apparition of +23° 25' 52" (+23°.43125 in decimal format), at which time the planet rises at its most Northerly point along the local horizon.
Venus' solar elongation falls below 10° West on July 8th and observers at both mid-Northern and mid-Southern latitudes lose sight of the planet over the following week. Around the third week of the month, observers at Equatorial and Tropical latitudes are the last to glimpse Venus as it disappears into the ENE horizon, bringing the planet's 2018-19 morning apparition to a close.
On July 24th Venus passes North of Mercury once more, the latter now about to head into the morning sky for its second morning apparition of 2019. The solar elongation of the two planets is, however, a mere 6° West of the Sun, so that this particular planetary conjunction is visible from nowhere on Earth.
Venus enters Cancer, the Crab, on July 26th.
2 0 1 9 August
Venus enters Leo, the Lion, on August 11th, reaching superior conjunction (passing behind the Sun as seen from the Earth) in the Western part of that constellation on August 14th. At the moment of conjunction the planet is positioned 1°.3 North of the Sun. Venus is now at a very distant 1.7312 AU (258.9 million kms or 160.9 million statute miles) from the Earth. Were it to be visible from the Earth at this point, Venus would have an apparent diameter of just 9".6 and would shine at magnitude -3.9.
Having passed from the morning to the evening sky, Venus remains out of view - lost in the solar glare - for a further three weeks, as it makes its slow passage on the far side of its orbit from the Earth. The planet becomes visible once again from around early September 2019, when it is seen from Equatorial latitudes as an 'Evening Star' in the Western sky shortly after sunset. This heralds the start of the 2019-20 evening apparition of Venus, which will last through to May 2020.
[Terms in yellow italics are explained in greater detail in an associated article describing planetary movements in the night sky.]
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Venus Conjunctions with other Planets:
Morning Apparition, 2019
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.
Planetary conjunctions are generally considered most noteworthy when they involve two bright planets, and none are more spectacular than those involving Venus. During the course of one Earth year, Venus is seen to complete over 1½ circuits of the zodiac, and in doing so it passes each of the planets in the sky - a few of them on more than one occasion.
Because Venus never appears more than 47° from the Sun, it follows that any planetary conjunction involving Venus will also never occur above this angular distance, i.e. its solar elongation will always be less than 47°. For an Earthbound observer, a superior planet (i.e. Mars and beyond) seen at such a small elongation poses something of a problem, since it will then be considerably more distant from the Earth - and therefore fainter - than when it is closest and brightest in the sky (namely, at opposition, when its elongation is 180° from the Sun). Jupiter is affected to a much lesser extent since it is always above magnitude -1.6 (brighter than Sirius, the brightest star in the sky).
A Conjunction of Venus and Jupiter took place on November 13th 2017, during a morning apparition of Venus (click on the thumbnail for the full-size picture, 97 KB). The planets were only 0°.3 apart and positioned 14° West of the Sun. The photo was taken by the writer about an hour before sunrise, when the pair were just 3° above the horizon.
A significant factor in determining whether a planetary conjunction is 'easy' or 'difficult' is the altitude that the fainter planet is positioned as it disappears from view in the dawn twilight. This in turn affects the duration for which the pair are visible after they rise. In this context, the four planetary conjunctions of 2019 will now be discussed.
Conjunctions between Venus and Jupiter are arguably the most spectacular to view, and fortunately the January 22nd 2019 conjunction between these two planets is also visible worldwide. It takes place only two weeks after Venus' greatest Western elongation, so it is about as far from the Sun as these two planets can appear at conjunction. The separation between the two is a rather wide 2°.4 - equivalent to almost five apparent Full Moon widths - so that the conjunction is more ideally viewed through binoculars rather than telescopes. Since the planets are positioned at a high Southerly declination at the moment of conjunction, the altitudes attained by the pair are relatively low when seen from mid- and high Northern latitudes. When Jupiter disappears from view in the dawn twilight, observers at latitude 60° North see the two planets attain an altitude of only 9° in the SSE whilst at 50° North the pair are just 16° high in the SSE. The altitudes and directions further South are as follows: 29° high in the South-east at 30° North, 41° high in the ESE at the Equator and 33° high in the East at 35° South.
The next best planetary conjunction of the apparition is on February 18th 2019, when Venus (mag. -4.0) passes 1°.1 to the North of Saturn (+0.6). For mid-Northern hemisphere observers, the planets' far Southerly position in the zodiac means that neither planet is placed particularly high in the sky when Saturn disappears from view. At 50° North the pair attain an altitude of just 9° above the South-eastern horizon when the ringed planet disappears from view, whilst at 30° North they only reach 21° high in the South-east. Equatorial and Southern latitudes have the best view; at the Equator they attain 34° high in the ESE whilst at 35° South they reach 33° high in the East.
The final two conjunctions of the apparition are not observable from high and mid-Northern latitudes and they involve the outermost planets Uranus and Neptune. Twilight quickly renders these planets unobservable (even through binoculars), so any conjunctions taking place less than about 20° from the Sun will be difficult or impossible to see. The conjunctions of 2019 are above that limit, at solar elongations of 23° and 33°, respectively.
Since Uranus and Neptune are the faintest of the observable planets in the night sky and Venus is the brightest, it follows that these conjunctions are technically difficult to observe - regardless of the solar elongation - and optical aid is required to observe such events. Through both telescopes and binoculars, Venus' brilliance means that it must be positioned outside the field of view to enable Uranus and Neptune to be comfortably seen.
On April 10th 2019 Venus (mag. -3.8) passes only 0º.3 South of Neptune (+7.9). Although rising in darkness, at latitude 30° North the two planets are placed a mere 4° above the Eastern horizon as Neptune disappears from view in the twilight, whilst even in the favourable Southern hemisphere the pair are placed only 18° high in the East at 35° South.
Venus and Uranus (+5.9) are involved in a relatively wide conjunction (1°.1) on May 18th 2019. The narrow solar elongation means that only observers located South of the Northern Tropics are able to view it. The planetary pair are positioned only 10° above the Eastern horizon as Uranus disappears from view.
Conjunctions between the inferior planets Venus and Mercury typically happen two or three times a year but many of them are too close to the Sun to observe; such is the case for the only conjunction between the two which takes place during the 2018-19 morning apparition.
The four planetary conjunctions with Venus which are observable during the 2018-19 morning apparition are summarised in the table below.
Venus conjunctions with other planets during the 2018-19 morning apparition (click on the thumbnail for the full-size table, 44 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 Venus, e.g. on 2019 Jan 22, Jupiter is positioned 2°.4 South of Venus at the time shown. The 'Fav. Hem' column shows the Hemisphere in which the conjunction is best observed (Northern, Southern and/or Equatorial). The expression 'Not high N/S Lats' indicates that observers at latitudes further North than about 45°N (or further South than about 45°S) will most likely find the conjunction difficult or impossible to observe because of low altitude and/or bright twilight.
In the 'When Visible' column, a distinction is made between Dawn and Morning visibility; the term Dawn refers specifically to the twilight period before sunrise, whilst the term Morning refers to the period 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 your particular latitude in the Rise-Set direction table.
The table is extracted from two other tables showing Venus conjunctions with other planets from 2010 to 2020 on the Venus Conjunctions page.
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. along 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 are technically more accurate (separations between planets 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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Moon near Venus Dates,
November 2018 to July 2019
The Moon is easy to find, and on one or two days in each month, it passes Venus in the sky. Use the following tables to see on which dates the Moon passes near the planet between November 2018 and July 2019:
Moon near Venus dates for the morning apparition of 2018-19 (click on the thumbnail for the full-size table, 29 KB). The Date Range shows the range of dates worldwide (allowing for Time Zone differences across East and West hemispheres). Note that the dates, times and separations at 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 (times are Universal Time [UT], 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 2nd 2019 at 04:16 UT, Venus is positioned 2°.7 South of the Moon's centre.
Because Venus never appears more than 47° from the Sun, the Moon always shows a crescent phase whenever it passes the planet in the sky: a waxing crescent during evening apparitions and a waning crescent during morning apparitions.
The Waning Crescent Moon and Venus in the Eastern sky before dawn, photographed by the writer on August 19th 2017 (click on the thumbnail for the full-size photo, 17 KB). Venus was positioned 2°.9 North of the Moon, as seen from the South-western United Kingdom. Note the effect of earthshine on the unlit portion of the Moon, caused by the Earth's reflected light.
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 have appeared closer to Venus 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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Copyright Martin J Powell October 2018
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