The Venus Morning Apparition
by Martin J. Powell
The Path of Venus through the Zodiac Constellations during the planet's morning apparition in 2014 (click for the full-size image, 46 KB). A version with constellation labels can be seen here (60 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 astronomers use to locate the position of a celestial body in the night sky. A print-friendly version is available here (21 KB).
After passing through inferior conjunction on January 11th 2014 (when it was positioned directly between the Earth and the Sun), Venus swiftly entered the dawn sky as a 'Morning Star' in mid-January 2014, visible low down in the ESE around 30-45 minutes before sunrise (the exact period depending upon the observer's latitude). The planet was positioned in the Northern-central region of Sagittarius, the constellation of the Archer, at this time.
Venus' solar elongation (its angular distance from the Sun) reached 10° West on January 16th, the planet moving retrograde (East to West) against the background stars and shining at an apparent magnitude of -4.0. The planet's apparent diameter at this time measured 1' (i.e. 1 arcminute, equal to 60 arcseconds).
During the latter half of January the planet's elongation increased rapidly from 10° West on the 16th to 29°W by month's end. As it pulled away from the Sun, telescopes pointed towards the planet showed a large, slender, Eastward-facing crescent, its apparent diameter shrinking slightly to around 50" (50 arcseconds) and brightening to magnitude -4.4. The planet's apparent diameter continued to shrink throughout the apparition, as it slowly receded from the Earth in space (click here to see how Venus typically appears through a small telescope at various phases).
At this early point in the 2014 apparition, dedicated telescopic observers of Venus began 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 by the surface of the planet glowing red hot. 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 Equatorial latitudes were best placed to view the Light at this stage of the apparition due to the planet's higher altitude (or elevation, i.e. the angle above the horizon) before sunrise.
Venus seen through a 6-inch Newtonian reflector telescope, sketched by Eric Graff during the planet's morning apparition in September 2007 (click to see the full-size sketch and description as it appears on the Astronomy Sketch of the Day website)
The planet briefly left Sagittarius and crossed the border into the non-zodiacal constellation of Ophiuchus, the Serpent Bearer, on January 25th. It stayed for just one week, re-entering Sagittarius again on the 31st.
Venus reached its Western stationary point on February 1st, positioned 6°.2 North-west of the star Albaldah ( Sgr or Pi Sagittarii, magnitude +2.9), one of a handful of stars which form the Archer's head.
For observers situated at high and mid-Northern latitudes, February saw the first of two altitude 'peaks' which took place during the planet's 2014 morning apparition (the other being in late July). In early February at 60° North latitude, Venus rose in the South-east some 2¼ hours before the Sun, attaining an altitude of 8° at 30 minutes before sunrise; here the planet was seen in twilight throughout the period. At 50° North in mid-February the planet was rising 2¼ hours before the Sun, reaching an altitude of 13° in the South-east at 30 minutes before sunrise.
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Venus attained its greatest brilliancy for this apparition (mag. -4.5) on February 11th 2014. This is the position in the planet's orbit when its phase (i.e. the percentage of the disk which is illuminated), its apparent size and its apparent magnitude combine to best visual effect, as seen from the Earth. At greatest brilliancy in the 2014 morning apparition, Venus was positioned 38° West of the Sun with a 23% illuminated crescent (phase = 0.23) and an apparent diameter of 42".6.
In late February, observers situated at Northern tropical latitudes saw the planet attain its highest altitude before sunrise for the 2014 morning apparition. At 30° North in mid-February, Venus rose 2½ hours ahead of the Sun, reaching 23° above the South-eastern horizon at half-an-hour before sunrise.
On March 6th the planet entered Capricornus, the Sea Goat, passing 1°.3 South of the star Dabih ( Cap or Beta Capricorni, mag. +3.0), the eye of the goat, on March 10th.
For Equatorial observers, March saw the planet attain its highest altitude above the horizon before sunrise. Mid-March, Venus rose three hours before the Sun, reaching 35° above the ESE horizon some 30 minutes ahead of sunrise.
Around 1am Universal Time (UT) on March 22nd, Venus passed 2°.7 North of Theta Capricorni ( Cap, mag. +4.0) and just five hours later crossed into the constellation of Aquarius, the Water Carrier. Later that same day the planet reached its greatest elongation from the Sun for this apparition (46°.5 West), positioned North of Theta Capricorni and 7°.7 WNW of the star Nashira ( Cap or Gamma Capricorni, mag. +3.7). Although positioned in Aquarius, Venus appeared much closer to the stars of Capricornus at this time, the nearest naked-eye Aquarian star being the fourth-magnitude Nu Aquarii ( Aqr, mag. +4.5) in the Western region of the Water Carrier. On greatest elongation day the planet was rising an hour before sunrise at 60° North, 1¾ hours before sunrise at 50° North and 2½ hours before sunrise at 30° North. Equatorial latitudes saw the planet rise three hours before the Sun and at mid-Southern latitudes the planet rose 3½ hours ahead of the Sun.
Telescopes now showed Venus' disk half-illuminated (phase = 0.50) with an apparent diameter of 24".5. Although the planet's greatest elongation from the Sun took place on March 22nd, Venus was in fact positioned at precisely 46°.5 elongation for an 11-day period from March 18th through to March 28th. The planet's apparent magnitude at this time was -4.3.
Theoretically, greatest elongation is the time at which the planet's terminator (the line seperating the light and dark sides of the planet) appears perfectly straight through telescopes, essentially dividing Venus into two perfect halves; this is known as the dichotomy. However, telescopic observers often report the straight terminator several days earlier or later than the greatest elongation date. Interestingly, the date of dichotomy is usually reported early in evening apparitions and late in morning apparitions. The precise reason for this phenomenon - which is referred to as Schröter's Effect - is not known, however it may simply be due to the fact that the precise moment of dichotomy cannot be determined by an observer to within an accuracy any better than a few days.
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Around this time, observers at mid-Southern latitudes saw Venus attain its highest altitude in the sky before sunrise for the 2014 apparition. At 35° South latitude in late March, the planet was rising over 3½ hours before the Sun, reaching an altitude of around 37° high in the East some 30 minutes before sunrise. In fact, when assessed in terms of horizon altitude and visibility duration before sunrise, the 2014 morning apparition of Venus was best seen overall from mid-Southern latitudes.
Venus returned to Capricornus on March 27th, passing 3°.9 North of the aforementioned Nashira three days later (30th), then 3°.8 North of the variable star Deneb Algiedi ( Cap or Delta Capricorni, mag. +2.9v) on April 1st.
Greatest elongation day having passed, telescopes showed a 55% illuminated (i.e. slightly gibbous) phase in early April. The phase remained gibbous throughout the rest of the apparition. The apparent diameter had now reduced to around 22" and the planet shone at an apparent visual magnitude of -4.2.
For observers at high-Northern latitudes, Venus had been rising in twilight for much of the apparition so far, barely gaining any significant altitude before disappearing into the advancing twilight. Naked-eye observers situated North of about 59° North lost the planet from view completely from around early April and did not see it again until about early July, when the Northern hemisphere summer twilight had begun to recede.
On April 3rd Venus re-entered Aquarius for the longer term, during which time the planet encountered a distant gas giant and was involved in a rare occultation of a naked-eye star. On April 8th Venus passed 2°.5 South of the fourth-magnitude star Ancha ( Aqr or Theta Aquarii, mag. +4.1) then on April 11th it crossed the ecliptic (the apparent path of the Sun through the zodiac) in a Southerly direction.
From around April 9th to 12th, Venus was positioned about ten degrees South of the asterism (star pattern) unofficially named The Steering Wheel in Northern Aquarius. At the centre of the 'wheel' is the star Zeta Aquarii ( Aqr, mag. +3.7) with the stars Sadachbia ( Aqr or Gamma Aquarii, mag. +3.9), Eta Aquarii ( Aqr, mag. +4.0) and Pi Aquarii ( Aqr, mag. +4.8) encircling it. It is one of several asterisms spread across the zodiac, named and un-named, which beginner astronomers should familiarise themselves with in order to aid constellation identification.
On April 12th Venus (now mag. -4.1) experienced the first of three planetary conjunctions which took place during the planet's 2014 morning apparition, when it passed 0°.7 North of the very-much-fainter planet Neptune (mag. +7.9). The visibility of this somewhat difficult conjunction from various latitudes across the world is shown in the Venusian planetary conjunctions table on the Naked-eye Venus page.
On April 16th Venus experienced a rare occultation of a naked-eye magnitude star, visible in darkness from Eastern Australia, Papua New Guinea and the Bismarck Archipelago. In astronomy, an occultation occurs whenever one body is seen to pass in front of another, temporarily obscuring the more distant body from view. The Moon regularly occults stars and sometimes planets, however it is considerably rarer for a planet to occult a relatively bright star. Between 2014 and 2040, for example, Venus occults 14 stars of magnitude +6 or brighter. The 2014 occultation of the star Lambda Aquarii ( Aqr, mag. +3.8) was only the second-brightest star to be occulted in that 26-year period (the brightest star being the aforementioned Pi Sagittarii of mag. +2.9, which Venus will occult in 2035). More details of this stellar occultation is given in the information box below.
Diagram showing the Cytherean occultation of the red giant star Lambda Aquarii ( Aqr, mag. +3.8) which took place on April 16th 2014 (Universal Time) during the planet's morning apparition (click on the thumbnail for full-size diagram, 55 KB). The occultation was visible just before dawn from Eastern Australia (East of Adelaide), Papua New Guinea and the Bismarck Archipelago. The event took place in twilight in New Zealand, New Caledonia and Vanuatu (note that from all of the above locations the occultation took place on April 17th local time). The diagram shows the occultation as it appeared from the Southern hemisphere (a Northern hemisphere view can be seen here [54 KB] but see the note below*).
Lambda Aquarii disappeared behind Venus' Eastern limb (position angle = 56°) at 18:03 UT (04:03 AEST/04:03 PGT/06:03 NZST) and re-appeared from behind its Western limb (p.a. = 263°) at 18:09 UT (04:09 AEST/04:09 PGT/06:09 NZST). Mid-point of occultation took place at about 18:07 UT.
The diagram shows the position of the star in relation to Venus at the time shown (UT), the planet being the fixed frame of reference. Hence Venus moved from South-west to North-east across the background stars, blocking out visibility of Lambda Aquarii for a period of about seven minutes. The planet was moving at a rate of about 3" (3 arcseconds) per minute. Venus was positioned 44° West of the Sun, measured 19".1 across and shone at magnitude -4.2 at the time of occultation. It was 61% illuminated (phase = 0.61).
Further information on the occultation, together with a map showing its visibility, can be found at the RASNZ Occultation Section website (where the star is referred to by its Hipparcos Catalog number HIP 112961).
*The occultation took place during daylight across the Americas, however the planet was above the horizon from these locations and telescopic observers with excellent sky conditions may have attempted to observe it.
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Venus passed 0°.3 North of the star Phi Aquarii ( Aqr, mag. +4.2) on April 21st. This star is positioned at the top of the Water Bearer's amphora, and it too will be occulted by Venus in 2028.
From around April 22nd through to April 29th, Venus was positioned about 7 degrees South of another asterism - this time in Pisces - appropriately named the Circlet of Pisces. It is positioned at the far-Western end of the constellation and it is the Fishes' most identifiable stellar feature. The planet itself moved into Pisces on April 28th, though between May 8th and 12th, Venus headed into the constellation of Cetus, the Whale, clipping its North-western corner.
Now back in Pisces, Venus crossed the celestial equator (where a celestial body's declination is 0°) on May 5th, positioned to the South-east of the Circlet. The planet was now rising due East across the inhabited world.
Venus' second planetary conjunction of the 2014 morning apparition took place on May 15th, when Venus (at mag. -3.9) passed 1°.2 South of the planet Uranus (mag. +5.9). The visibility of this conjunction from across the world is shown in the planetary conjunctions table on the Naked-eye Venus page.
By mid-May Venus' elongation had reduced to 40° and it had dimmed slightly to magnitude -3.9. It was distinctly gibbous through telescopes, showing a 73% illuminated phase and a disk-diameter of around 15". The planet was now rising in the East 1¼ hours before sunrise at 50° North, 2 hours before sunrise at 30° North, 2½ hours before sunrise at the Equator and 3¼ hours before sunrise at 35° South.
The last reasonably bright star encountered by Venus before leaving Pisces was the star Torcularis Septentrionalis ( Psc or Omicron Piscium, mag. +4.2). The planet passed 0°.4 South of this star on May 27th.
On the last day of May, Venus entered the constellation of Aries, the Ram, passing a significant 12°.6 South of its leading star Hamal ( Ari or Alpha Arietis, mag. +2.1) on June 1st.
After an uneventful passage through the Ram, the planet entered Taurus, the Bull, on June 17th. Taurus contains a wealth of interesting deep-sky objects (i.e. objects which are positioned beyond our Solar System), amongst them being the star cluster known as The Pleiades or, less commonly, The Seven Sisters (Messier 45). Venus passed about 6 degrees South of this famous cluster on June 22nd. Such was the apparent rate of motion of the planet against the background stars that it traversed the angular distance of The Pleiades in just 22 hours. From June 29th to July 2nd, Venus passed to the North of another, much larger star cluster: the Hyades, a 'V'-shaped grouping of stars which form the head of the Bull.
The 'eye' of the Bull is marked by the orange-red star Aldebaran ( Tau or Alpha Tauri, mag. +0.9), a red giant which is not actually part of the true Hyades group of stars; it is in fact a foreground star, closer to the Earth than the cluster (the cluster lies at a distance of about 150 light years whereas Aldebaran is just 66 light years away). Having reduced elongation to 30° West of the Sun, Venus passed 4°.2 to the North of Aldebaran on July 2nd. By the following day the planet's magnitude had fallen to -3.8 and it stayed this bright for the remainder of the apparition.
Both The Pleiades and the Hyades are examples of zodiacal asterisms which were referred to previously. More obvious to the novice astronomer will be the constellation of Orion, the Hunter, which was positioned to the South of the planet during mid-July. Before leaving Taurus and entering Orion on July 16th, Venus passed 0°.4 North of the Crab Nebula (M1 or NGC 1952) on July 13th and 1°.3 North of Zeta Tauri ( Tau, mag. +2.9) - at the tip of the Bull's Southern horn - on July 14th.
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In mid-July Venus shared the same region of the morning sky with its fellow inferior planet Mercury, coming to within six degrees of the planet on the 17th. Mid-month, the planet was positioned to the ESE of Venus, shining at about zero magnitude and positioned some 20° West of the Sun. Mercury reached greatest elongation from the Sun on July 12th - when its solar elongation was 21° West - and was now slowly drawing back in towards the Sun. This was Mercury's second morning apparition of 2014 and its fourth of the year so far (the planet had six full apparitions in 2014; three in the morning and three in the evening).
Venus spent just two days in the non-zodiacal constellation of Orion, passing a short distance North of the Hunter's club. On July 18th the planet returned to the zodiac proper when it entered Gemini, the Twins, passing 0°.3 North of the star Tejat Prior ( Gem or Eta Geminorum, mag. +3.5v) on July 21st. Two days later (23rd) Venus passed 0°.3 North of Tejat Posterior ( Gem or Mu Geminorum, mag. +3.0) and attained its most Northerly declination (symbol ) for this apparition ( = +22°.83). Across the world, the planet was now rising at its most Northerly point along the local horizon; the actual point of rising depending upon the observer's latitude. At 60° North in mid-July, Venus rose in the North-east; at mid-Northern latitudes it was more towards the ENE; at Equatorial latitudes it was also in the ENE whilst at mid-Southern latitudes it was in the North-east.
During late July and into August, observers at high and mid-Northern latitudes saw the planet attain a secondary altitude 'peak'. At latitude 60° North, some 30 minutes before sunrise, the planet attained an altitude of 9° above the North-eastern horizon - only 1 degree higher than in early February and even this was not very high, but it was the best that observers at these latitudes got during the 2014 apparition. Mid-Northern observers fared little better; 30 minutes before sunrise, the planet reached just 12° above the ENE horizon, almost the same altitude as back in February but further North along the local horizon. Telescopically the planet appeared 90% illuminated and, at barely 11" across, little could be discerned in the way of cloud markings. This of course held true for observers at all latitudes, regardless of the planet's local altitude before sunrise.
Over the next fortnight, Venus passed the bright stars which form the pattern of the two Gemini figures. On July 25th the planet passed 6°.4 North of Alhena ( Gem or Gamma Geminorum, mag. +1.9) at the foot of the Southern twin, then on the 27th, 2°.3 South of Mebsuta ( Gem or Epsilon Geminorum, mag. +3.0) positioned at the groin of the Northern twin. On July 30th Venus passed 1°.9 South of Mekbuda (Gem or Zeta Geminorum, mag. +3.9v) at the right knee of the Southern twin.
As August arrived the planet's solar elongation had reduced to 22° and its visibility across the world was becoming more limited. At 60° North the planet was rising in twilight about 2¼ hours before the Sun, reaching 9° above the ENE horizon some 30 minutes before sunrise. At mid-Northern latitudes Venus was rising about 2 hours ahead of the Sun, reaching 11° high in the ENE at 30 minutes before sunrise. Equatorial and Northern Tropical latitudes saw the planet rise about 1¾ hours before the Sun, reaching 13° high in the ENE at 30 minutes before sunrise. Mid-Southern hemisphere observers now had a rapidly shortening window in which to observe the planet, despite it rising in near-darkness. At 35° South, Venus rose 1¼ hours ahead of the Sun, attaining just 8° in altitude in the North-east at 30 minutes before sunrise.
Venus rising at dawn (click for full-size picture, 206 KB). The star visible to the lower right of Venus is Spica, the brightest star in Virgo (Copyright Martin J Powell, 2012)
The planet crossed the ecliptic from South to North on August 2nd, then on the following day - soon after midnight (UT) - passed just 10' (10 arcminutes or 0°.16) to the North of the star Wasat ( Gem or Delta Geminorum, mag. +3.5). Finally, Venus passed 10° South of Castor ( Gem or Alpha Geminorum, mag. +1.6) on August 5th and 6°.5 South of the constellation's brightest star Pollux ( Gem or Beta Geminorum, mag. +1.1) on August 7th. Castor and Pollux mark the head of the Northern and Southern twin, respectively. The two bright stars appeared to 'point the way' to the 'Morning Star' at dawn on August 11th, by which time the planet had moved into the constellation of Cancer, the Crab.
Venus left Gemini and entered the much fainter stars of Cancer on August 10th, passing 11°.1 North of the star Altarf ( Cnc or Beta Cancri, mag. +3.5) on August 13th. Over recent weeks the planet had been slowly closing in on Jupiter, also positioned in Cancer, at the rate of about 1° per day. Jupiter was now emerging in the dawn sky at the start of its 2014-15 apparition, moving direct (prograde) against the background stars. By the morning of August 17th the two planets were just 1° apart and closing rapidly. Around 04:00 UT on August 18th, Venus passed just 12' (0°.2) North of Jupiter in a spectacular morning conjunction, the planets being some 18° away from the Sun. The separation between the duo was sufficiently narrow to enable both planets to be viewed through a telescope within the same field of view in a low-power eyepiece, providing an interesting photographic opportunity for those with the equipment to do so. Binocular users and naked-eye observers need not have lost out, however; with Venus shining at magnitude -3.8 and Jupiter at -1.6, the two appeared as a close, very bright double star, separated by about the distance of the famous naked-eye double Mizar (UMa or Zeta Ursae Majoris, mag. +2.0) and Alcor (80 UMa or 80 Ursae Majoris, mag. +4.0) in Ursa Major, the Great Bear.
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The planetary conjunction took place in brightening twilight, the two planets not attaining any great altitude above the ENE horizon by the time Jupiter (the fainter of the two) disappeared from view. At latitude 60° North, the duo reached an altitude of 7° by the time twilight overwhelms Jupiter; the altitudes for other latitudes were 9° (at 50° North), 12° (at 30° North), 11° (at the Equator) and just 4° (at 35° South). The conjunction evidently favoured Northern hemisphere observers due to the planets' Northerly declinations; the Southern limit of visibility was about latitude 43° South.
At the time of conjunction the duo were positioned just 0°.8 South-west of the open cluster called Praesepe or The Beehive Cluster (M44), a faint scattering of stars in central Cancer. Unfortunately the narrow solar elongation of this planetary conjunction meant that, on this particular morning, the star cluster was only visible from Equatorial latitudes - and even then only for a short while - before being lost in the rapidly brightening twilight. After conjunction the planets began to pull apart, and by the time Venus itself was positioned due South of Praesepe at around 14:00 UT the same day, the angular distance between the two had widened to almost 0°.5.
On August 19th Venus passed between the stars Asellus Borealis ( Cnc or Gamma Cancri, mag. +4.7) and Asellus Australis ( Cnc or Delta Cancri, mag. +3.9) which flank the Eastern side of Praesepe. The planet passed 38' (0°.6) North of Asellus Australis, which is about one-fifth of the distance between the two stars. Only observers at Northern tropical latitudes were able to observe this, Venus being positioned barely 3° above the ENE horizon one hour before sunrise.
On August 22nd Venus passed 6°.1 to the North of the star Acubens ( Cnc or Alpha Cancri, mag. +4.2), which is located at the South-eastern corner of the 'lambda-shaped' figure of Cancer, before entering Leo, the Lion, on the 26th. By August 29th the planet was just 15° from the Sun and was rising in twilight across the inhabited world. For most of the Southern hemisphere the 'observing window' had reduced to less than an hour. Venus' high declination put it in rather better sight of Northern hemisphere observers; the planet rose 1¾ hours before the Sun at 60° North, 1½ hours before the Sun at 50° North and 1¼ hours before the Sun at 30° North, attaining about 8° in altitude some 30 minutes before sunrise.
During the first week of September the planet was positioned South of the asterism known as the Sickle of Leo which comprises six stars forming the head and mane of the Lion. Since the Lion faces West, it appears as a backward question-mark () with the brightest star of the group, Regulus ( Leo or Alpha Leonis, mag. +1.4) at its base; its other, relatively faint stars were likely to be difficult to discern in the dawn twilight, however. Venus passed 0°.7 North of Regulus on September 5th and by the 10th the planet's solar elongation had reduced to just 10°.
Venus entered Virgo on September 24th, by which time it was a mere 8° West of the Sun and fast heading out of view from most Earthbound locations. The planet became lost from view in the dawn twilight by the start of October, reaching superior conjunction (passing behind the Sun as seen from the Earth) in South-eastern Virgo on October 25th 2014.
Having passed from the morning to the evening sky, Venus remained out of view - lost in the solar glare - for about a month, as it made its slow passage on the far side of its orbit from the Earth. The planet became visible once again from around late November 2014, when it was seen shortly after sunset in the Southern hemisphere as an 'Evening Star' in the WSW, heralding a new evening apparition (2014-15) which lasted through to August 2015.
[Terms in yellow italics are explained in greater detail in an associated article describing planetary movements in the night sky.]
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Copyright Martin J Powell January 2014
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