The Venus Evening Apparition
of 2014 to 2015
by Martin J. Powell
The paths of Venus, Mercury and Jupiter through the zodiac constellations during the latter part of Venus' evening apparition in 2014-15 (click on the thumbnail for the full-size version, 195 KB). The former part of the planet's apparition appears in the star chart below. Positions of Venus and Mercury are plotted for 0 hrs Universal Time (UT) at 5-day intervals; Jupiter's position is plotted on the 1st of each month. For Venus, apparition data for the dates shown in bright white (at 10-day intervals) are included in the table below.
Both evening and morning apparitions of Mercury are included. Wherever a planet was too close to the Sun to view, the path is shown by a dashed line (- -). Hence Mercury's evening apparition drew to a close in late May 2015. It then became lost from view in the evening twilight as it headed towards inferior conjunction with the Sun. The planet then re-emerged in the dawn twilight in early June for a morning apparition which lasted into mid-July. Because Mercury is mostly seen in twilight, many of the fainter stars shown in the planet's vicinity may not have been visible when the planet itself was observed.
The positions at which Mercury and Venus attained greatest elongation from the Sun are indicated by the letters 'GE', with the solar elongation angle in brackets; it is Eastern (E) in the evening and Western (W) in the morning (the elongation of Venus is Easterly throughout the chart coverage). The April-May 2015 evening apparition of Mercury favoured Northern hemisphere observers whilst the morning apparition of June-July favoured Southern hemisphere observers (who should refer to the Southern hemisphere chart (198 KB) for a more appropriate orientation).
The faintest stars shown on the chart have an apparent magnitude of about +4.8. Printer-friendly versions of this chart are available for Northern (92 KB) and Southern hemisphere (87 KB) views. Astronomical co-ordinates of Right Ascension (longitude, measured Eastwards in hrs:mins) and Declination (latitude, measured in degrees North or South of the celestial equator) are marked around the border of the chart.
Click here to see a 'clean' star map of the area (i.e. without planet paths); a printable version can be found here.
Planetary conjunctions between Venus and Jupiter took place on two occasions during the period, at the beginning and end of July; these are indicated on the chart by the symbol . For more details see the planetary conjunctions section below. The path of Jupiter on this chart also appears on the Jupiter 2014-18 chart.
Following superior conjunction on October 25th 2014 (when it passed directly behind the Sun in the constellation of Virgo) Venus' 2014-15 apparition as an 'Evening Star' commenced as the planet emerged in the dusk sky around mid-November 2014. Observers at Equatorial latitudes were the first to see it, low down in the Western sky soon after sunset. Northern latitudes began to detect the planet from around late November (at 30° North), early December (40° North), mid-December (50° North) and late December (60° North). Southern latitudes detected the planet from between mid-November (at 15° South) and late November (35°-45° South). Venus was moving in an Easterly direction (direct or prograde) through the constellations of Ophiuchus, the Serpent Bearer and Sagittarius, the Archer, at this time, its solar elongation (angle measured from the Sun) being less than 10°.
2 0 1 4 December
On December 13th Venus attained its most Southerly position in the zodiac for the 2014-15 apparition, with a declination (symbol ) of -24° 12' 16" (i.e. 24°.204 South of the celestial equator), just inside the Western border of Sagittarius. Venus now set at its most Southerly point along the local horizon. By late December the planet was setting around an hour after sunset.
2 0 1 5 January
Venus entered Capricornus, the Sea-Goat, on January 3rd 2015, its elongation having extended to 17° East of the Sun. During January the planet moved at a rate of 1°.25 per day against the background stars, positioned a little South of the ecliptic (the apparent path of the Sun, Moon and planets).
At this early stage of the apparition, when seen through a telescope, the planet showed a broad gibbous shape (i.e. a little less than a full disk), its phase (the percentage of the illuminated portion of the disk) being around 96%. The planet shone at an apparent magnitude of -3.8 and its apparent diameter measured only a little over 10" across (i.e. 10 arcseconds, where 1" = 1/60th of an arcminute or 1/3600 of a degree). The planet's low altitude (angle above the horizon), its great distance from the Earth and its small apparent size made Venus a difficult object to observe telescopically, with no detail being visible in its clouds.
^ Back to Top of Page
On January 10th the planet Mercury came to within 0°.6 of Venus, having approached it from the West, out of the solar glare and into its first evening apparition of 2015. Mercury reached greatest Eastern elongation (its greatest angular distance from the Sun during this apparition) a few days later on January 14th, positioned 19° East of the Sun and shining at an apparent magnitude of -0.5. This was the first of seven apparitions which Mercury underwent during the course of 2015 (three in the morning and four in the evening).
Up until this point, at half-an-hour after local sunset, Venus had been positioned over the South-western or WSW horizon, its altitude no higher than about 10° above the horizon. From mid-January Venus' position along the local horizon at any given time after sunset began to move slowly Northwards over the coming months and the planet's altitude also increased; movements which would continue through to mid-May. The rate of altitude increase was relatively fast in the Northern hemisphere but more gradual in the Southern hemisphere. During the 2014-15 evening apparition it was the Northern hemisphere which first saw Venus attain its highest point in the sky after sunset (in late Spring); the Southern hemisphere would witness this about a month or two later (in early Winter). Details of the planet's direction and altitude at 30 minutes after sunset for various latitudes are listed in the table below and they are also shown in the form of a horizon diagram.
On January 22nd Venus, shining at magnitude -3.8, passed 1°.1 North of the star Deneb Algiedi ( Cap or Delta Capricorni, mag. +2.9) in Eastern Capricornus. The planet entered Aquarius, the Water Carrier, a few days later on January 25th. Around this time Venus was setting some 2 hours after sunset (at high-Northern latitudes), 1¾ hours after sunset (at low and mid-Northern latitudes), 1½ hours after sunset (Equatorial and Tropical latitudes) and 1¼ hours after sunset (mid-Southern latitudes).
2 0 1 5 February
With the arrival of February, Venus encountered the first of six planetary conjunctions which the planet underwent during the 2014-15 evening apparition. A planetary conjunction occurs when two planets attain the same celestial longitude, such that they can often appear very close together in the night sky. The February 1st conjunction with Neptune was, however, the worst of the six, Neptune being the faintest of the observable planets in the night sky. For more details of this difficult-to-view conjunction, see the planetary conjunctions section below.
By early February Venus' solar elongation had extended to 25° and its apparent size had increased slightly to a little over 11". The apparent disk size would continue to increase as the apparition progressed. Telescopes showed a notably gibbous phase about 90% illuminated.
On February 5th Venus passed 1°.1 South of the star Lambda Aquarii ( Aqr, mag. +3.8) in central Aquarius. The planet had passed in front of this star during its 2014 morning apparition, blocking it from view for several minutes (an event called an occultation).
Venus entered Pisces, the Fishes, on February 16th. From around 11th-16th the planet passed about 7° South of the asterism (star pattern) named the Circlet of Pisces, a circular pattern of moderately-bright stars at the far-Western end of the constellation.
Table of selected data relating to the evening apparition of Venus during 2014-15 (click on the thumbnail for the full-size table, 76 KB). The data is listed at 10-day intervals, corresponding with the dates shown in bright white on the star charts 1 and 2. The data for the table was obtained from 'MegaStar', 'Redshift 5' and 'SkyGazer Ephemeris' software and the Venusian disk images were derived from NASA's Solar System Simulator.
^ Back to Top of Page
February 21st saw the second planetary conjunction involving Venus during its 2014-15 evening apparition. Mars, now a dim, +1.2 magnitude object, was in the final months of its 2013-15 apparition, having reached opposition back in April 2014. Venus, still at mag. -3.8, passed 0°.4 South of the Red Planet, positioned precisely on the celestial equator (declination = 0°) and only a short distance away from the Vernal Equinox point (Right Ascension = 0h 0m 0s). This point is also referred to as the First Point of Aries and it is marked on the star chart by a Ram symbol (). The Venus-Mars conjunction favoured Northern hemisphere observers but was poorly positioned for Southern hemisphere observers; for further details, see the planetary conjunctions section below.
On February 26th Venus exited the zodiac temporarily, clipping the North-western corner of the constellation of Cetus, the Whale and spending around 33 hours there before returning to Pisces the following day.
2 0 1 5 March
Uranus, the seventh planet from the Sun and the most distant planet visible with the naked-eye, had been positioned in Pisces since 2009, and on March 4th Venus passed just 0°.1 to the North of it. This planetary conjunction was well-positioned for Northern hemisphere observers and, although Uranus was only just above naked-eye visibility, it was an interesting event to observe through binoculars and telescopes as dusk fell (more details below).
Venus crossed the ecliptic from South to North on March 15th and entered Aries, the Ram, on the 16th. The planet was positioned a wide 10°.2 South of the constellation's brightest star Hamal ( Ari or Alpha Arietis, mag. +2.1) on March 21st (the planet exited Chart 1 around March 19th, following which there was a 12-day 'gap' in chart coverage before Venus re-appeared on Chart 2 in early April). The planet passed 0°.8 South of the Ram's Easternmost bright star Botein ( Ari or Delta Arietis, mag. +4.3) on April 3rd.
By late March Venus had brightened to magnitude -3.9, its apparent diameter had increased to 13".6 and its illuminated phase was around 80%. With the elongation now approaching 40° East of the Sun, the planet was setting 4 hours after sunset (at high-Northern latitudes), 3 hours after sunset (at low and mid-Northern latitudes), 2½ hours after sunset (at Northern Tropical latitudes), 2 hours after sunset (Equatorial and Southern Tropical latitudes) and 1½ hours after sunset (mid-Southern latitudes).
2 0 1 5 April
Venus entered Taurus, the Bull, on April 7th, passing around 3° South of the famous star cluster known as The Pleiades (pronounced 'PLY-add-eez' or 'PLEE-add-eez'), also called The Seven Sisters (Messier 45), between April 10th and 11th. From April 17th to 21st, Venus passed around 6½° North of the much larger star cluster called the Hyades (from the ancient Greek word for 'rain'). It is a distinct 'V'-shaped grouping of stars which form the head of the Bull. At the South-eastern corner of the 'V' shape, marking the 'eye' of the Bull, is the orange-red star Aldebaran ( Tau or Alpha Tauri, mag. +0.9). 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 closer to the Earth than the cluster. Venus passed 7°.6 North of Aldebaran on April 21st.
The paths of Venus, Mercury and Mars through the zodiac constellations during the former part of Venus' evening apparition in 2014-15 (click on the thumbnail for a full-size image, 184 KB). The latter part of the planets' apparition is shown in the chart above. Planet positions are plotted for 0 hrs Universal Time (UT) at 5-day intervals. The paths of Uranus and Neptune are also shown for reference.
Both evening and morning apparitions of Mercury are included. Wherever a planet was too close to the Sun to view, the path is shown by a dashed line (- -). Hence Mercury's evening apparition ended around late January 2015 when it became lost from view in the dusk twilight. The planet was then unobservable for about 2 weeks before it re-emerged in the morning sky in early February. Because Mercury is mostly seen under twilit conditions, many of the fainter stars shown in the planet's vicinity may not have been visible when the planet itself was observed.
For Venus, apparition data for the dates shown in bright white (at 10-day intervals) are included in the table above. The positions at which Venus and Mercury attained greatest elongation from the Sun are indicated by the letters 'GE', with the solar elongation angle in brackets. Eastern elongations apply for evening apparitions and Western elongations for morning apparitions (the elongation of Venus is Easterly throughout the chart coverage). The position at which Venus attained greatest brilliancy for this apparition (apparent magnitude = -4.5) is shown by the letters 'GB'. Note that the January 2015 evening apparition of Mercury shown on the chart favoured Northern hemisphere observers whilst the February-March morning apparition favoured Southern hemisphere observers (who should refer to the Southern hemisphere chart (188 KB) for a more appropriate orientation).
The faintest stars shown have an apparent magnitude of about +4.8. Printer-friendly versions of this chart are available for Northern (85 KB) and Southern hemisphere (86 KB) views. Astronomical co-ordinates of Right Ascension (longitude, measured Eastwards in hrs:mins) and Declination (latitude, measured in degrees North or South of the celestial equator) are marked around the border of the chart. Click here to see a 'clean' star map of the area (i.e. without planet paths); a printable version can be found here.
During the 2014-15 evening apparition, planetary conjunctions took place between Venus and all four planets shown on the chart; these are indicated by the symbol . For more details see the planetary conjunctions section below. Mars' 2013-15 apparition is described in full on the Mars 2013-15 page.
^ Back to Top of Page
Throughout April, Venus was seen at its highest altitude after sunset (for the current apparition) from high-Northern latitudes. At latitude 60º North the planet was positioned 25º above the Western horizon at 30 minutes after sunset. Because of the combination of the planet's high declination and the shallow setting angle of celestial objects at these high latitudes, Venus was above the horizon for a remarkable 4½-5 hours after sunset. From these latitudes, however, twilight began to interfere with observation later in the month as the Northern hemisphere summer approached.
2 0 1 5 May
From around mid-April to mid-May, observers at mid-Northern latitudes saw the planet at its highest altitude after sunset during this apparition. At latitude 40º North in early May, some 30 minutes after sunset, Venus was positioned a significant 32º high in the West, setting over 3½ hours after the Sun (see direction and altitude table below).
By the beginning of May Venus had brightened to magnitude -4.0 and its solar elongation was more than 40° from the Sun. The planet had become an interesting telescopic object with an apparent diameter of around 17" and showing a gibbous, 65% illuminated phase. Venus was now about one Astronomical Unit (AU) from the Earth, i.e. the same approximate distance as the Earth is from the Sun.
On May 1st the planet passed 3° South of the star Al Nath or El Nath ( Tau or Beta Tauri, mag. +1.6) which marks the tip of the Bull's Northern horn. The star also carries the name Gamma Aurigae ( Aur) since, apart from defining one of the Bull's horns, it also neatly completes the six-sided figure comprising the stars of Auriga, the Charioteer, located to the North-east of Taurus. The star marking the tip of the Bull's Southern horn is Zeta Tauri ( Tau, mag. +2.9v) and Venus passed 4°.6 North of it on May 3rd.
On May 8th Venus entered Gemini, the Twins, where it soon attained its most Northerly declination for this apparition ( = +26° 2' 19" or +26°.038). Across the world, the planet now set at its most Northerly point along the local horizon, the actual point of setting depending upon the observer's latitude. For example, at 60° North in early May, Venus set in the North-west, while at mid-Northern latitudes it set in the West-North-west (WNW).
On May 17th Venus passed 0°.7 North of the star Mebsuta ( Gem or Epsilon Geminorum, mag. +3.0) which is positioned at the groin of the Northern twin, who is identified from ancient Greek mythology as the legendary Argonaut named Castor. On May 25th Venus passed 2°.9 North of the star Wasat ( Gem or Delta Geminorum, mag. +3.5) at the groin of the Southern twin (another Argonaut, named Pollux).
The names of the Twins are retained in the names of Gemini's two brightest stars, which mark the position of their heads. Castor ( Gem or Alpha Geminorum, mag. +1.6) is the more Northerly and the fainter of the two; Venus passed 7°.4 South of it on May 28th. The planet passed 4° South of the brighter star Pollux ( Gem or Beta Geminorum, mag. +1.1) on May 30th.
From mid-May observers at high-Northern latitudes began to note the planet's altitude at any given period after sunset falling away with each passing day; thirty minutes after sunset the planet was placed around 25° high in mid-May but it had fallen to about 15° by mid-June (see horizon diagram for 55° North below).
In late May, observers at Northern Tropical latitudes saw the planet attain its highest altitude after sunset for the 2014-15 apparition. At latitude 20º North Venus was positioned 37º high in the WNW at 30 minutes after sunset, setting 3¼ hours after the Sun.
2 0 1 5 June
On June 2nd the stars Castor and Pollux appeared to 'point the way' to Venus in the dusk sky, the exactitude of the three-object line-up being dependant on the observing time and position on Earth. The exact time of line-up was around 12:30 Universal Time (UT, equivalent to GMT), so that observers in Eastern Asia and Western Australia were best positioned to see it. The distance between Castor and Venus was about 10°, with Pollux in between. The appearance (orientation) of this line-up in relation to the local horizon was dependant upon the observer's latitude. At 30° North, some 1½ hours after sunset, the line-up appeared parallel to the horizon, 20° high in the WNW. At 45° South, some 1¼ hours after sunset, the line-up appeared perpendicular to the horizon, around 8° high in the North-west. Elsewhere the line-up took on a variety of graceful angles to the local horizon when observed at least an hour after local sunset.
Details of the brighter star clusters, nebulae and interesting stars of Aries, Taurus and Gemini can be found on the Zodiacal Sky page covering these constellations.
^ Back to Top of Page
Venus entered Cancer, the Crab, on June 3rd. Three days later (June 6th) the planet reached its greatest elongation from the Sun for this apparition (45°.38 East), positioned 8°.6 South-east of Pollux and about 6½° North-east of the Praesepe star cluster in central Cancer (see below). At this point, telescopes showed Venus' disk half-illuminated (phase = 0.50 or 50%) with an apparent diameter of 23".5 and shining at magnitude -4.2. Although the greatest elongation from the Sun took place on June 6th, Venus was in fact positioned at 45° elongation for a six-day period from June 4th through to the 9th.
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 is not fully understood. Observers often report the straight terminator several days earlier or later than the greatest elongation date (early in evening apparitions and late in morning apparitions). This anomaly is commonly known as Schröter's Effect.
It is often assumed that when Venus is positioned at its greatest angular distance from the Sun that this will be the time at which the planet will be visible for the longest period. In fact, this is not entirely true because the duration of visibility of the planet after sunset depends not only upon its solar elongation but also upon the observer's latitude and the time of year that the greatest elongation takes place. The observer's latitude will determine the angle at which the planet descends towards the horizon at setting; this angle will be steep around the Equator but shallow towards the poles. The time of year determines the angle at which the planet is positioned above the local horizon after sunset; if the ecliptic presents a steep angle to the horizon after sunset the planet will be visible for longer than when the ecliptic presents a shallow angle to the horizon. Add to this the changing length of twilight (caused by the changing seasons) which affects the actual visibility of the planet against the background sky, then one will understand why the situation is not as straightforward as one might first assume.
This having been said, in 2015 the period during which Venus could be seen after sunset on greatest elongation day was remarkably consistent across most inhabited latitudes. The planet was visible for about 3¼ hours, give or take just a few minutes. This is in stark contrast to the duration of visibility on greatest elongation day at most other evening apparitions, as a glance at the table on the Venus Conjunctions page shows only too clearly. The apparent height of the planet above the horizon at any given period after sunset, and the direction in which it is seen, does of course vary with latitude, and for the 2015 apparition, these are shown the table below.
For telescopic observers of Venus, a high placement of the planet in the sky after sunset - whether or not this takes place around greatest elongation day - is of little benefit. Because of the planet's glare when seen against a darkening sky, coupled with the Earth's troublesome atmospheric turbulence at low altitudes, most telescope users observe the planet in full daylight, when it is high above the horizon and more easily seen against a brighter sky. Of course, extreme caution must be taken when attempting to observe any of the planets in daylight and the Sun must be positioned at a safe angular distance from the planet and be fully shielded from view.
With greatest elongation day having passed, the planet's phase changed from gibbous to crescentic, i.e. with a phase of less than 50%. Telescopically the next two months would prove most interesting as the crescent became more slender in appearance and enlarged day by day as the planet drew closer to the Earth in space.
Between June 12th and 13th Venus passed about 1° North of the open cluster Praesepe (pronounced 'pree-SEE-pee') also known as The Beehive Cluster (M44 or NGC 2632). The planet took about 29 hours to move the angular width between the cluster's Westernmost naked-eye star (Electra or 17 Tau, mag. +3.7) and its Easternmost naked-eye star (Atlas or 27 Tau, mag. +3.6). On June 14th Venus passed between the stars Asellus Borealis ( Cnc or Gamma Cancri, mag. +4.6) and Asellus Australis ( Cnc or Delta Cancri, mag. +3.9), passing about 1º.1 South of the Northernmost star (Borealis). The distance between the two stars - measured from North to South - is 3º.3. Finally the planet passed a sizeable 7º.2 North of Acubens ( Cnc or Alpha Cancri, mag. +4.3), at the South-eastern corner of Cancer's lambda-shaped () figure.
^ Back to Top of Page
Around mid-June Venus was best seen from Equatorial latitudes. Here the planet stood 37º above the WNW horizon at 30 minutes after sunset, remaining visible for 3¼ hours thereafter. In fact, when taken in terms of the planet's visual impact and its ease of viewing, the 2014-15 evening apparition of Venus was best seen overall from Equatorial latitudes. In addition, twilight is brief around the Equator throughout the year, so the planet was mostly seen in truly spectacular fashion against a fully dark sky.
Also from mid-June, observers situated at mid-Northern latitudes began to see Venus' altitude at any given period after sunset fall increasingly rapidly day-by-day. Thirty minutes after sunset, the planet was positioned some 28º above the horizon in mid-June but it had fallen to just 14º by mid-July (see horizon diagram for 35° North below). South of about 50º North latitude the planet was also seen to 'backtrack' somewhat, heading a little Southwards along the horizon. This is due to the fact that Venus was now moving Southwards in declination - i.e. it was moving South-eastwards through Cancer - causing its apparent position along the horizon to also head Southward. This 'backtracking' was more evident the further South an observer was located.
In late June, observers at Southern Tropical latitudes saw Venus at its best for the 2014-15 evening apparition. Half an hour after sunset, the planet was positioned 33º above the North-western horizon (a third of the way 'up the sky'), setting around 3¼ hours after the Sun.
By late June Venus had brightened to magnitude -4.4 and its apparent diameter had swollen to over 30", some three times the size it had appeared back in early February. With an illuminated crescentic phase of 35% the planet was a beautiful sight when seen through even the smallest of telescopes.
Venus entered Leo, the Lion, on June 26th, the final zodiacal constellation in which the planet was seen during the 2014-15 evening apparition. Over the next month the planet occupied only the South-western corner of the Lion constellation, positioned to the South of the Sickle of Leo asterism. Venus encountered the giant planet Jupiter twice during this time.
From late June, observers at higher-Northern latitudes began to have some difficulty viewing Venus as it sank into the bright summer twilight, setting around 1½ hours after the Sun. Meanwhile observers located South of the Northern Tropics continued to enjoy views of the 'Evening Star' in darkness, positioned around 30° high at 30 minutes after sunset and visible for around 3 hours after sunset.
In late June and early July, observers at mid-Southern latitudes finally got their chance to see Venus at its highest and best for this apparition. At 35º South, some 30 minutes after sunset, Venus was placed 29º high in the North-western sky, setting around 3½ hours after the Sun. In stark contrast, high-Northern latitudes now saw the planet setting only an hour after sunset, the altitude of the planet being only 5° or so above the horizon at 30 minutes after sundown.
2 0 1 5 July
Jupiter, magnitude -1.6, was now in the closing stage of its 2014-15 apparition, having spent about half of this period in Cancer and the other half in Leo. The planet was moving direct (prograde) when Venus caught up with it on July 1st and passed just 0°.4 to the South of the giant planet in a spectacular and close planetary conjunction - the best of its 2014-15 evening apparition. The conjunction was best seen from the Southern hemisphere, however much of the Northern hemisphere also got a good view. Again, further details can be found in the planetary conjunctions section below.
Venus crossed to the South of the ecliptic on July 5th. As it entered Leo its daily South-eastward motion against the background stars was slowing; whilst in Cancer in the previous month the planet had been moving at a rate of about 1° per day, but now it was moving at about half that rate.
From early July observers at Equatorial latitudes began to see Venus reduce noticeably in altitude at any given period after sunset. The best of the show now over, the planet fell from 34° high (at 30 minutes after sunset) at the start of July to just 11° at the end of the month; a fall of about 0°.75 in altitude per day (see horizon diagram for the Equator below).
Venus attained its greatest brilliancy for this apparition (mag. -4.5) on July 12th at around 05:00 UT. This occurs when its illuminated phase and its angular size combine to best visual effect. For the 2014-15 apparition, this took place when the planet was 25% illuminated (phase = 0.25), its angular diameter was 38".4 and its solar elongation was 38°.
Around mid-month Venus moved significantly Southwards against the background stars, pulling further away from the ecliptic plane, and its solar elongation narrowed from 37° (on July 15th) to 23° (at month's end). This slow Southward movement slightly improved the visibility of the planet after sunset from Southern hemisphere latitudes, despite its reducing elongation, but it increasingly worsened its visibility from Northern latitudes.
^ Back to Top of Page
From mid-June to mid-July, some thirty minutes after sunset, observers at mid-Southern latitudes had been enjoying views of Venus of around 30° high. However the planet's altitude began to fall significantly after mid-month. From an altitude of around 28° (at 30 minutes after sunset) in mid-July, Venus fell to just 17° at month's end, a fall of about 0°.8 in altitude per day. The rate of descent would become even more rapid in August (see horizon diagram for 30° South below).
On July 14th Venus was positioned 2°.4 to the South-west of Leo's brightest star Regulus ( Leo or Alpha Leonis, mag. +1.4) but it never reached conjunction with it. Descriptions of the interesting deep-sky objects and stars in Cancer and Leo can be found on the Zodiacal Sky page covering these constellations.
Venus' Eastward motion ceased on July 23rd when it reached its Eastern stationary point, positioned some 3º.8 to the SSW of Regulus and 6º.3 to the South-east of Jupiter. Venus then started to move retrograde (East to West) and its solar elongation reduced more rapidly with each passing day. Around mid-July, observers at high-Northern latitudes lost Venus from the evening sky as it disappeared into the bright dusk twilight.
Jupiter, now with only several days of visibility left in the brightening twilit sky, was positioned 6°.4 to the North of Venus on July 31st. Despite the wide separation this was still technically a planetary conjunction, although at an elongation of just 20° East of the Sun it was a difficult one to view (see below).
Towards the end of July, observers at mid-Northern latitudes began to have some difficulty viewing Venus as its altitude fell below 10° (at 30 minutes after sunset), setting about an hour later. At 50° North the planet set precisely at 30 minutes after sunset. Elsewhere Venus set 1½ hours after the Sun (at Equatorial and Northern Tropical latitudes), 2 hours after the Sun (at Southern Tropical latitudes) and 2¼ hours after the Sun (at mid-Southern latitudes). However, the lengthy visibility of the planet from Southern latitudes was destined to be short-lived, as the planet dropped rapidly in altitude with each passing day.
2 0 1 5 August
Since mid-May the planet's Southward movement along the horizon had been much more evident from mid-Southern latitudes. Thirty minutes after sunset, Venus had moved from the North-west at the start of June to the WNW by the start of August, which translated to a drift of about 37° along the horizon in a period of two months (see horizon diagram for 30° South below).
Venus left the zodiac for a second time on August 3rd when it nudged across Leo's Southern border into Hydra, the Water Snake. Two days later the planet experienced its final planetary conjunction of this apparition, when it passed 8°.2 South of Mercury (mag. -0.7). With a solar elongation of just 13°, this difficult conjunction was only seen from Equatorial and Southern hemisphere latitudes.
As the apparition drew to a close in late July and early August, observers equipped with binoculars may have attempted to detect the tiny crescent of Venus soon after sunset as it languished low in the Western sky. Telescopes showed a large, thin crescent at this point, over 50" in diameter, the image greatly disturbed by the Earth's turbulent atmosphere and split into the rainbow colours by an effect called dispersion (an example of how dispersion appears through a telescope can be seen here).
As the Venusian crescent continued to enlarge it also became more slender, so that the dark (non-illuminated) side of the planet was well-displayed when seen from the Earth. With the aid of ultraviolet and infrared filters, telescopic observers now began their search for the mysterious and elusive Ashen Light, a faint glowing of the night side of Venus which has no clear explanation. The Ashen Light is considered 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 the planet's dense atmosphere. Intriguingly, reports of the Ashen Light have been rare in recent years, though it is difficult to say whether this is the result of improved observing equipment (i.e. eliminating contrast effects caused by poor optics) or a true reduction in activity of a genuine phenomenon.
Also around this time, observers with exceptionally-good eyesight may have attempted to view the crescent of Venus with the naked-eye. Whilst this may seem extraordinary, the planet's apparent size of around 50" brings it very close to the generally-accepted resolution limit of the human eye, i.e. 1 arcminute (60"). Because the planet's solar elongation was now around 15° or less, glare was no longer a problem because the planet was now seen in bright twilight through to its setting, theoretically allowing the crescent to be discerned more easily.
By the end of the first week of August Venus had become lost from view from latitudes North of the Equator; by the time the planet returned to Leo on August 14th, it was lost from the remainder of the inhabited world.
Venus sped towards inferior conjunction (passing between the Earth and the Sun) which it reached on August 15th 2015. At the moment of inferior conjunction, Venus was positioned at the South-western edge of Leo, some 7º.8 South of the Sun's centre (ecliptic latitude = -7º.8). After inferior conjunction, the planet headed into the morning sky. About a week later, Venus was sighted again from Southern latitudes, rising in the Eastern sky as a 'Morning Star' shortly before the Sun, heralding a new morning apparition (2015-16) which lasted through to April 2016.
[Terms in yellow italics are explained in greater detail in an associated article describing planetary movements in the night sky.]
^ Back to Top of Page
Venus Conjunctions with other Planets in 2015
Easily the best planetary conjunction of Venus' 2014-15 evening apparition was that with Jupiter on July 1st. The separation of the two planets (0°.4) was much closer than the spectacular conjunction of March 2012 - the previous best conjunction between these two planets - which caught the attention of the public worldwide and received appreciable media attention. The 2012 conjunction was ideally positioned for Northern hemisphere observers, however the July 2015 conjunction was best seen from the Southern hemisphere. Observers at 30° South saw the conjunction positioned 32° high in the North-west as Jupiter became visible in the dusk twilight. The pair were seen against a fully dark sky for over 1½ hours before setting.
The conjunction was visible at dusk at higher Northern latitudes (i.e. the planets were seen against a twilit sky) and was not visible at all North of about 58° North latitude. Elsewhere the two planets were seen in darkness after twilight ended, the primary factor affecting their duration of visibility being their altitude above the local horizon when Jupiter first became visible in the twilight. Although more favourable to Southern hemisphere observers, the conjunction could be seen at a decent altitude as far North as about 40° North. At 35° North, for example, the two planets were positioned about 24° high over the Western horizon as Jupiter became visible. Observers equipped with telescopes at low magnification would likely have attempted to view the two planets together in the eyepiece. Since the glare of Venus (mag. -4.3) was likely to prove problematic, photographing the event during twilight may have been the best option.
Thirty days after the first conjunction with Jupiter, there was a second, on July 31st. The elongation of the two planets on this occasion, however (20° E) was less than half that of the July 1st conjunction, so that this event was much more difficult to observe. It was also visible from a much narrower band of latitudes; it could not be seen North of about 35° North and was difficult from latitudes further South. Seen from the Equator, as Jupiter became visible in the twilight, the planets were positioned just 13° above the Western horizon. The two planets were seen in darkness for a short period in Southern latitudes though the altitude was low. With a wide separation of 6°.4 some may not have considered this conjunction to be worthwhile viewing. The planetary duo were too far apart to be contained within the field of view of telescopes, however binoculars would have easily accommodated them.
A conjunction with Mars on February 21st took place during the closing months of the Red Planet's 2013-15 apparition. Mars was now a feeble, ruddy-coloured +1.2 magnitude 'star', some ten months past opposition. Venus, at mag. -3.8, passed 0°.4 South of Mars, so that the two planets were easily contained within a telescopic eyepiece view at low power. However, with an apparent diameter of 11".8, the disk of Venus was nearly three times larger than that of Mars, and it was correspondingly much brighter. The Venus-Mars conjunction was ideally placed for Northern hemisphere observers although the elongation (28° E) was relatively narrow. The duo were poorly positioned for Southern hemisphere observers; indeed, the conjunction could not be viewed South of about latitude 37° South.
Venus passed just 0°.1 to the North of Uranus on March 4th. Taking place only 11 days after the Mars conjunction, the two planets were well-positioned for Northern hemisphere observers. At latitude 40° North the pair stood 20° above the Western horizon as Uranus became visible in the dusk twilight. At mid-Northern latitudes the pair could be observed in darkness for a little over half-an-hour before setting. The elongation of 31° was slightly better than the Mars conjunction, however, unlike the Red Planet, Uranus (mag. +5.9) was only just above naked-eye visibility. This close conjunction was an interesting event to observe through telescopes, the duo being easily contained within a telescopic eyepiece view, although Venus' characteristic glare would certainly have proved a problem in this case. Mars itself was located some 5° to the SSW of the pair, positioning it closer to the horizon. Southern hemisphere observers would have found the pair positioned low above the Western horizon as dusk fell (only about 9° high as Uranus became visible at 30° South) giving very little time for successful observation. Twilight and low altitude rendered the conjunction unobservable South of about latitude 35° South.
On February 1st Venus was in conjunction with Neptune, then at magnitude +7.9. Since Neptune is the faintest of the observable planets in the night sky and Venus is the brightest, it follows that this conjunction was a difficult one to observe, regardless of the solar elongation. Telescopes were required to observe it; binocular users would have found that the brilliance of Venus (mag. -3.8) prohibited comfortable viewing. Even through telescopes Venus' brilliance meant that it had to be positioned outside the telescopic field of view to enable Neptune to be comfortably seen. The conjunction was best seen from Northern latitudes, the Northern and Southern limits of visibility being about 56° North and 19° South, respectively. At best, Northern Tropical latitudes saw the pair at just 10° above the Western horizon when Neptune was first glimpsed in the dusk twilight. The altitude fell away the further North or South one was located from the Northern Tropics: at both 50° North and 15° South latitudes, for example, the planets were just 6° high as Neptune became visible.
Conjunctions between Venus and Mercury typically happen two or three times a year but many of them are too close to the Sun to observe; even when they are visible they are often difficult to see because of their narrow solar elongation. The only observable conjunction between the two inferior planets during the 2014-15 evening apparition was a difficult one to observe, taking place on August 5th, near the close of the apparition when the pair were just 13° East of the Sun. It could only be seen from Equatorial and Southern hemisphere latitudes. Venus (mag. -4.0) and Mercury (mag. -0.7) were separated by a wide 8°.2, the planets being located in different constellations at the time of the conjunction. Jupiter was positioned a short distance to the North-east of the pair.
The six planetary conjunctions with Venus which were viewable during the 2014-15 evening apparition are summarised in the table below.
Venus conjunctions with other planets during 2015 (click on the thumbnail for the full-size table, 23 KB) Note that there were no observable planetary conjunctions involving Venus during late 2014. 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 2015 Jul 1, Jupiter was positioned 0°.4 North of Venus at the time shown. The 'Fav. Hem' column shows the Hemisphere in which the conjunction was best observed (Northern, Southern and/or Equatorial). The expression 'Not high N Lats' indicates that observers at latitudes further North than about 45°N will most likely have found 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 Dusk and Evening visibility; the term Dusk refers specifically to the twilight period after sunset, whilst the term Evening refers to the period after darkness falls (some conjunctions take place in darkness, others do not, depending upon latitude). The 'Con' column shows the constellation in which the planets were positioned at the time of the conjunction.
To find the direction in which the conjunctions were seen on any of the dates in the table, note down the constellation in which the planets were located ('Con' column) on the required date and find the constellation's setting direction for your particular latitude in the Rise-Set direction table.
The table is modified from another 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. 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 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.
^ Back to Top of Page
Moon near Venus Dates,
December 2014 to July 2015
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 passed near the planet between December 2014 and July 2015:
Moon near Venus dates for the evening apparition of 2014-5 (click on the thumbnail for the full-size table, 26 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 March 22nd at 19:50 UT, Venus was positioned 2°.8 North 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 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.
^ Back to Top of Page
Direction, Altitude & Visibility Duration
of Venus after Sunset,
December 2014 to August 2015
The following tables give the direction and altitude (angle above the horizon) of Venus at 30 minutes after sunset, together with the duration of visibility of the planet after sunset, for the 2014-15 evening apparition. An explanation of abbreviations in the tables is given in the box below. For the sake of convenience, the table is split into Northern and Southern hemisphere latitudes (the Equator is included in both tables to allow interpolation of the data for observers situated at Equatorial latitudes). The tables should prove sufficient to locate the planet in twilight, allowing telescope users to view the planet in comfort (because of Venus' brilliance, glare becomes a problem when the planet is seen through the eyepiece against a dark sky). Direction and Altitude diagrams are also provided below for intermediate latitudes of 55° North, 35° North, 30° South and the Equator.
The tables allow one to find the highest altitude in the sky which Venus attained for any given latitude during the 2014-15 evening apparition, and in which direction it was seen. For example, observers situated at latitude 40° North will have found the planet highest in the sky (at 30 minutes after sunset) in early May 2015, when it was seen at an altitude of 32° towards the West. The duration column shows that the planet was viewable for a little over 3½ hours after sunset.
Direction & Altitude (30 minutes after local sunset) and Visible Duration of Venus for Northern hemisphere latitudes and the Equator for the evening apparition of 2014-15 (click on the thumbnail for the full-size table, 107 KB; for Southern hemisphere latitudes and the Equator, click here, 97 KB). To find your latitude, visit the Heavens Above website, select your country and enter the name of your nearest town or city in the search box.
The table column headings are as follows:
Dir = compass direction of Venus,
Alt = angular altitude (elevation) of Venus (degrees above the horizon; a negative value of Alt means Venus is below the horizon).
Dur = the approximate visibility duration of Venus after local sunset (in hrs:mins). An italicised duration means that Venus was seen under twilight conditions through to its setting, i.e. it was not seen against a truly dark sky (twilight in this case refers to nautical twilight, which ends when the Sun is more than 12° below the horizon). A hyphen (-) indicates that Venus set in daylight.
Note that the directions and altitudes refer to the planet's position at 30 minutes after local sunset. To find the time of local sunset at your own location, select your country/town from the drop-down menu at the Time and Date.com website. The approximate time at which Venus set can be found by adding the visibility duration on a particular date (column Dur) to the time of local sunset on the same date. To find the direction in which Venus set on any given date for a particular latitude, note down the constellation in which the planet was located on the required date (column headed Con) then find its setting direction for your latitude in the Rise-Set direction table.
^ Back to Top of Page
Direction & Altitude Diagrams (Horizon Diagrams)
for the 2014-15 Evening Apparition
The following diagrams show an observer's Western horizon (from due South to due North) for latitudes of 55° North (a high-Northern latitude), 35° North (mid-Northern), the Equator and 30° South (mid-Southern). The path of Venus is plotted in the sky at 30 minutes after local sunset throughout the 2014-15 evening apparition with the planet's direction and altitude marked along the horizontal and vertical axes, respectively. Essentially, these diagrams show the same information as in the above look-up tables, but in an illustrative format, for the Equator and three intermediate latitudes.
Below: Paths of Venus in the Evening Sky (30 mins after sunset) for the 2014-15 evening apparition, as seen by observers at latitudes 55° North, 35° North, the Equator and 30° South (click on a thumbnail for a full-size image, ca. 130 KB each). The letters GE refer to the planet's greatest elongation (followed in brackets by its angular distance from the Sun) and the letters GB refer to the planet's greatest brilliance point (followed in brackets by its apparent magnitude).
The azimuth (Az, along the bottom of each diagram) is the bearing measured clockwise from True North (where 0° = North, 90° = East, 180° = South, etc.). The altitude (Alt) is the angle measured vertically from the local horizon (the horizon itself is 0° and the point directly overhead is 90°). Azimuth and altitude are co-ordinates which are used for high-accuracy tracking of objects across the sky; in astronomy it is mainly used for setting telescopes which are fitted with altazimuth mounts.
To determine the planet's position in the sky with higher accuracy, an overlay grid is provided for each diagram. The overlay grids are marked at 10° intervals in azimuth and altitude (the dates are removed for clarity). For example, at latitude 35° North on June 1st 2015, at 30 minutes after sunset, Venus was found at azimuth = 277° (i.e. in the West) and altitude = 32°.
The Path of Venus in the Evening Sky (plotted for 30 mins after sunset) during 2014-15 for an observer at latitude 55° North. Click here (125 KB) for the overlay grid.
The Path of Venus in the Evening Sky (plotted for 30 mins after sunset) during 2014-15 for an observer at latitude 35° North. Click here (112 KB) for the overlay grid.
The Path of Venus in the Evening Sky (plotted for 30 mins after sunset) during 2014-15 for an observer at the Equator (latitude 0°). Click here (108 KB) for the overlay grid.
The Path of Venus in the Evening Sky (plotted for 30 mins after sunset) during 2014-15 for an observer at latitude 30° South. Click here (98 KB) for the overlay grid.
Although the dates indicated in the above diagrams refer specifically to the period 2014-15, Venus has an 8-year cycle of apparitions such that its position in the evening sky in 2014-15 will repeat very closely in the evening sky of 2022-23. The writer refers to this particular evening apparition as Apparition F1; for more details, see the accompanying article describing The Venus 8-year Cycle.
^ Back to Top of Page
Copyright Martin J Powell December 2014
Site hosted by TSOHost