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Direction, Altitude & Visibility Duration of Venus after Sunset, 2011-2012:

Look-up Tables

Horizon Diagrams

2011-12 Evening Apparition Data

The Transit of Venus, June 5th-6th 2012

Venus Conjunctions with other Planets, 2012

Moon near Venus Dates, Sep 2011 to May 2012

The Venus Evening Apparition of 2010

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Star chart showing the paths of Venus, Mercury, Jupiter and Uranus through Aquarius, Pisces, Aries and Taurus from mid-January to early June 2012 (Copyright Martin J Powell 2011)

 

The Paths of Venus, Mercury, Jupiter and Uranus through the zodiac constellations for the latter part of Venus' evening apparition in 2012, which culminated in a rare transit of Venus across the Sun on June 5th-6th 2012 (see here for more details). The earlier part of the planets' apparition is shown in the chart below. Positions of Venus and Mercury are plotted for 0 hrs Universal Time (UT) at 5-day intervals; those of Jupiter and Uranus are for the 1st of each month. 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 mid-March 2012 when it became lost from view in the dusk twilight. The planet was then not visible for about 2 weeks before it re-emerged in the morning sky in late March. Because Mercury is only ever seen under twilit conditions, many of the fainter stars shown in the planet's vicinity would 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 below. 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 = -4.4) is shown by the letters 'GB'. Note that the February-March 2012 evening apparition of Mercury shown on the chart favoured Northern hemisphere observers, whilst the April-May morning apparition favoured Southern hemisphere observers (who should refer to the Southern hemisphere chart for a more appropriate orientation).

Conjunctions of Venus with Uranus and Jupiter in 2012 took place on February 10th and March 15th respectively; for more details see the planetary conjunctions section below. On these dates, a line drawn vertically through the respective planet paths show them to be in alignment. The path of Jupiter on this chart is excerpted from the Jupiter 2011-14 chart whilst that of Uranus is excerpted from the Uranus 2006-19 chart.

The faintest stars shown have an apparent magnitude of about +4.8. Printer-friendly versions of this chart are available for Northern and Southern hemisphere 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.

The Venus Evening Apparition of 2011 to 2012 by Martin J Powell

Following superior conjunction on August 16th 2011 (when it passed directly behind the Sun in the constellation of Leo) Venus' 2011-12 apparition as an 'Evening Star' began as the planet emerged in the dusk sky in late September 2011. The time of year at which the planet became visible depended upon the observer's latitude; Equatorial and Southern latitudes were first to see it, low down in the West shortly after sunset. The further North the observer was located, the later the planet emerged; hence high-Northern latitudes did not begin to see Venus until around late November 2011.

The planet was slow to emerge from the twilight glow, taking several weeks to gain a significant altitude (angle above the horizon) after sunset. At this early stage of the apparition, when seen through a telescope, the planet showed a broad gibbous phase, around 98% illuminated, shining at an apparent magnitude of -3.8 and measuring only around 10" across (i.e. 10 arcseconds, where 1" = 1/60th of an arcminute or 1/3600 of a degree). Its low altitude, great distance from the Earth and small apparent size made it a difficult object to observe telescopically, with no detail being visible in its clouds. The planet was positioned in central Virgo as the apparition began, moving South-eastwards along the ecliptic (the apparent path of the Sun, Moon and planets) at a steady rate of about 1.2 per day.

On September 30th 2011, Venus passed 1.3 South of Saturn, in an event known as a planetary conjunction. However, Saturn's 2010-11 apparition was now drawing to a close and at magnitude +0.9 it was barely bright enough to see, low down in the dusk twilight. From Southerly latitudes, Venus, at magnitude -3.8, was more easily discerned in the twilight.

From early to mid-October, observers in Northern Tropical latitudes began to detect the planet, low in the West after sunset. Having spent five weeks in Virgo, the Virgin, Venus entered Libra, the Balance (or Scales) on October 15th. Now at a more comfortable solar elongation of 18, the planet passed 9' South (i.e. 9 arcminutes, where 1' = 1/60th of a degree) of the double star Zuben Elgenubi (Greek lower-case letter alpha Lib or Alpha Librae, mag. +2.8) on October 21st. Around this time, mid-Northern latitudes began to detect the planet, low in the West-South-west after sunset.

From around October 22nd, Venus was joined from the West by Mercury, now emerging into the evening sky for an apparition which favoured Southern hemisphere observers. At this point in time, Mercury's apparent motion against the background stars was swifter than that of Venus, so that Mercury slowly closed in on Venus over the next couple of weeks. Venus entered the constellation of Scorpius, the Scorpion, on November 2nd, followed only hours later by Mercury on the same day. Five days later (on November 8th) Venus entered Ophiuchus, the Serpent Bearer, Mercury following it several hours later on November 9th. The two planets came closest together on November 9th, being 2 apart, although they did not actually reach conjunction (see below for details of other planetary conjunctions with Venus during the 2011-12 apparition).

Venus, Mercury and the orange-red star Antares (Greek lower-case letter alpha Sco or Alpha Scorpii, mag. +1.0 [v]) formed an interesting line-up 3.9 in length on November 10th, Venus being the most Northerly of the three with Mercury at the centre. The line-up was only visible from latitudes South of about 30 South.

Mercury briefly exited Ophiuchus and re-entered Scorpius on November 12th, reaching its greatest elongation from the Sun on November 14th, when it was positioned 23 East of the Sun and shone at an apparent magnitude of -0.2. The planet spent just three days in Scorpius before returning to Ophiuchus on November 15th. Its apparent motion also began to slow, so that Venus began to pull away from Mercury towards the East. Mercury reached its Eastern stationary point on November 24th, at which point it was positioned 6.7 to the West of Venus. Mercury's evening apparition ended only days later as it disappeared from view into the dusk twilight.

On November 23rd 2011, Venus entered Sagittarius, the Archer, the most Southerly constellation of the zodiac. Six days later (November 29th) the planet attained its most Southerly position in the zodiac for the 2011-12 apparition, with a declination of -24.76 (i.e. 24.76 South of the celestial equator). Venus then set at its most Southerly point along the local horizon, an effect which was more pronounced the further away from the Equator an observer was situated.  For example, at the Equator (latitude 0) Venus set in the West-South-west at this time whilst at 55 North (where observers were only just beginning to see it) the planet set in the South-west, some 20 further South along the horizon.

From November 27th to December 9th 2011, Venus passed to the North of the asterism (star pattern) commonly known as The Teapot. Seen in a North-up orientation, the teapot appears 'tipped up', pouring its contents South-westwards into neighbouring Scorpius. The asterism extends from the star Al Nasl (Greek lower-case letter 'gamma' Sgr or Gamma Sagittarii, mag. +3.0) in the West to the star Tau Sagittarii (Greek lower-case letter 'tau' Sgr, mag. +3.3) in the East. On December 1st Venus passed 42' (0.7) North of Kaus Borealis (Greek lower-case letter 'lambda' Sgr or Lambda Sagittarii, mag. +2.8) at the top of the teapot and five days later (December 6th) the planet passed 1.9 North of the constellation's second-brightest star Nunki (Greek lower-case letter 'alpha' Sgr or Alpha Sagittarii, mag. +2.0) in the handle of the teapot. Finally, on December 8th Venus passed 5.6 North of the star Ascella (Greek lower-case letter 'zeta' Sgr or Zeta Sagittarii, mag. +2.6) at the base of the teapot's handle.

Date

Constellation

Apparent

Magnitude

Apparent

Diameter

(arcsecs)

View from

Earth

(0h UT)

(North up)

Distance (AU)*

Solar

Elongation

Illuminated

Phase

from Earth

from Sun

2011

Sep 19

Astrological symbol for Virgo

Vir

-3.8

9".8

View of Venus from Earth on September 19th 2011 at 0h UT (Image modified from NASA's Solar System Simulator v4)

1.6950

0.7213

9E

99%

Sep 29

Astrological symbol for Virgo

Vir

-3.8

9".9

View of Venus from Earth on September 29th 2011 at 0h UT (Image modified from NASA's Solar System Simulator v4)

1.6737

0.7226

12E

98%

Oct 9

Astrological symbol for Virgo

Vir

-3.8

10".1

View of Venus from Earth on October 9th 2011 at 0h UT (Image modified from NASA's Solar System Simulator v4)

1.6480

0.7239

14E

97%

Oct 19

Astrological symbol for Libra

Lib

-3.8

10".3

View of Venus from Earth on October 19th 2011 at 0h UT (Image modified from NASA's Solar System Simulator v4)

1.6183

0.7252

17E

96%

Oct 29

Astrological symbol for Libra

Lib

-3.8

10".5

View of Venus from Earth on October 29th 2011 at 0h UT (Image modified from NASA's Solar System Simulator v4)

1.5848

0.7264

19E

95%

Nov 8

Astrological symbol for Scorpius

Sco

-3.8

10".8

View of Venus from Earth on November 8th 2011 at 0h UT (Image modified from NASA's Solar System Simulator v4)

1.5476

0.7273

22E

93%

Nov 18

 

Oph

-3.8

11".1

View of Venus from Earth on November 18th 2011 at 0h UT (Image modified from NASA's Solar System Simulator v4)

1.5072

0.7279

24E

92%

Nov 28

Astrological symbol for Sagittarius

Sgr

-3.8

11".4

View of Venus from Earth on November 28th 2011 at 0h UT (Image modified from NASA's Solar System Simulator v4)

1.4635

0.7281

26E

90%

Dec 8

Astrological symbol for Sagittarius

Sgr

-3.8

11".8

View of Venus from Earth on December 8th 2011 at 0h UT (Image modified from NASA's Solar System Simulator v4)

1.4167

0.7280

29E

88%

Dec 18

Astrological symbol for Sagittarius

Sgr

-3.8

12".2

View of Venus from Earth on December 18th 2011 at 0h UT (Image modified from NASA's Solar System Simulator v4)

1.3668

0.7275

31E

86%

Dec 28

Astrological symbol for Capricornus

Cap

-3.9

12".7

View of Venus from Earth on December 28th 2011 at 0h UT (Image modified from NASA's Solar System Simulator v4)

1.3140

0.7267

33E

84%

2012

Jan 7

Astrological symbol for Capricornus

Cap

-3.9

13".3

View of Venus from Earth on January 7th 2012 at 0h UT (Image modified from NASA's Solar System Simulator v4)

1.2582

0.7256

35E

81%

Jan 17

Astrological symbol for Aquarius

Aqr

-3.9

13".9

View of Venus from Earth on January 17th 2012 at 0h UT (Image modified from NASA's Solar System Simulator v4)

1.1995

0.7244

37E

79%

Jan 27

Astrological symbol for Aquarius

Aqr

-3.9

14".7

View of Venus from Earth on January 27th 2012 at 0h UT (Image modified from NASA's Solar System Simulator v4)

1.1378

0.7230

39E

76%

Feb 6

Astrological symbol for Pisces

Psc

-4.0

15".5

View of Venus from Earth on February 6th 2012 at 0h UT (Image modified from NASA's Solar System Simulator v4)

1.0732

0.7217

41E

73%

Feb 16

Astrological symbol for Pisces

Psc

-4.0

16".6

View of Venus from Earth on February 16th 2012 at 0h UT (Image modified from NASA's Solar System Simulator v4)

1.0057

0.7205

42E

69%

Feb 26

Astrological symbol for Pisces

Psc

-4.0

17".8

View of Venus from Earth on February 26th 2012 at 0h UT (Image modified from NASA's Solar System Simulator v4)

0.9355

0.7195

44E

65%

Mar 7

Astrological symbol for Aries

Ari

-4.1

19".3

View of Venus from Earth on March 7th 2012 at 0h UT (Image modified from NASA's Solar System Simulator v4)

0.8628

0.7188

45E

61%

Mar 17

Astrological symbol for Aries

Ari

-4.2

21".2

View of Venus from Earth on March 17th 2012 at 0h UT (Image modified from NASA's Solar System Simulator v4)

0.7878

0.7184

46E

56%

Mar 27

Astrological symbol for Aries

Ari

-4.2

23".5

View of Venus from Earth on March 27th 2012 at 0h UT (Image modified from NASA's Solar System Simulator v4)

0.7113

0.7185

46E

51%

Apr 6

Astrological symbol for Taurus

Tau

-4.3

26".3

View of Venus from Earth on April 6th 2012 at 0h UT (Image modified from NASA's Solar System Simulator v4)

0.6337

0.7189

46E

45%

Apr 16

Astrological symbol for Taurus

Tau

-4.3

30".0

View of Venus from Earth on April 16th 2012 at 0h UT (Image modified from NASA's Solar System Simulator v4)

0.5565

0.7196

44E

39%

Apr 26

Astrological symbol for Taurus

Tau

-4.4

34".7

View of Venus from Earth on April 26th 2012 at 0h UT (Image modified from NASA's Solar System Simulator v4)

0.4814

0.7207

42E

31%

May 6

Astrological symbol for Taurus

Tau

-4.4

40".6

View of Venus from Earth on May 6th 2012 at 0h UT (Image modified from NASA's Solar System Simulator v4)

0.4112

0.7219

37E

22%

May 16

Astrological symbol for Taurus

Tau

-4.3

47".6

View of Venus from Earth on May 16th 2012 at 0h UT (Image modified from NASA's Solar System Simulator v4)

0.3507

0.7233

29E

13%

May 26

Astrological symbol for Taurus

Tau

-4.1

54".3

View of Venus from Earth on May 26th 2012 at 0h UT (Image modified from NASA's Solar System Simulator v4)

0.3071

0.7246

17E

4%

 

Jun 6

Astrological symbol for Taurus

Tau

-3.6

57".8

View of Venus from Earth on June 6th 2012 at 0h UT, during a transit of the Sun (Image modified from NASA's Solar System Simulator v4)

0.2887

0.7260

0

0%

* 1 AU (Astronomical Unit) = 149,597,870 kms (92,955,806 statute miles)

Table of selected data relating to the evening apparition of Venus during 2011-2012. The data is listed at 10-day intervals, the latter part corresponding with the dates shown in bright white on the star maps (top of page). 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 v4.

Around this time, observers at mid-Southern latitudes saw Venus attain its highest altitude in the sky after sunset for the 2011-12 apparition. At 45 South latitude in early December, Venus was around 15 high at 30 minutes after sunset, the planet itself setting over two hours after the Sun. At 35 South in mid-December, the planet attained 18 altitude at 30 minutes after sunset. The significance of the observer's latitude in observing planets at narrow solar elongations was well illustrated at this time; whilst mid-Southern hemisphere observers were enjoying their best views of Venus around mid-December, observers at 60 North latitude were only just catching their first glimpse of the planet after sunset (details of the planet's direction and altitude at 30 minutes after sunset for various latitudes are listed in the table below).

On December 20th 2011 Venus entered Capricornus, the Sea Goat, passing 6.5 South of the constellation's second-brightest star Dabih (Greek lower-case letter 'beta' Cap or Beta Capricornus, mag. +3.1) on December 22nd. The Northern hemisphere winter solstice now having passed, both Venus and the Sun began to ascend the ecliptic once more. With the declination of both celestial bodies moving Northwards and the solar elongation of Venus continuing to increase over the next few months, the setting positions of both Venus and the Sun moved further North along the local horizon with each passing week. Venus passed 1.3 South of Theta Capricornus (Greek lower-case letter 'theta' Cap, mag. +4.0) on December 31st and 27' (0.45) South of Iota Capricornus (Greek lower-case letter 'iota' Cap, mag. +4.2) on January 4th 2012. The Sea Goat's tail stars of Nashira (Greek lower-case letter 'gamma' Cap or Gamma Capricornus, mag. +3.7) and Deneb Algiedi (Greek lower-case letter 'delta' Cap or Delta Capricornus, mag. +2.9) were passed to the North by Venus on January 7th and 9th, the separations being 52' (0.86) and 57' (0.95) respectively.

By late December 2011, Venus was setting in darkness from all but the Polar regions of the world. Shining brightly above the rooftops after dark during the festive season, the planet was easily associated with the 'Star of Bethlehem' in the Nativity story. This particular 'star', however, was seen in the West and not in the East.

With the arrival of 2012, Venus had brightened to -3.9 and its apparent size had reached 13". Telescopes showed a notably gibbous phase, about 80% illuminated. On January 11th 2012 Venus entered the constellation of Aquarius, the Water-Bearer. Soon afterwards the planet exited the Chart 1 coverage, after which it encountered the planet Neptune, which had entered the constellation in January 2011 and will remain there until 2022. On January 13th the Solar System's brightest and faintest naked-eye planets came to within 1.1 of each other in the Earth's night sky, some 36 East of the Sun, Neptune being the more Northerly of the two. Since Neptune is always below naked-eye visibility, this planetary conjunction required optical aid. However, the sheer brilliance of Venus (at mag. -3.9) and the faintness of Neptune (mag. +7.9) made it an uncomfortable conjunction to view. Four hours after its conjunction with the distant planet, Venus passed 29' (about the apparent width of the Full Moon) to the North of the fourth-magnitude star Tau Aquarii (Greek lower-case letter 'iota' Aqr).

As Venus re-joined the star chart coverage in Chart 2 (top of page), it was positioned in central Aquarius, some 4.5 South of the star Ancha (Greek lower-case letter 'theta' Aqr or Theta Aquarii, mag. +4.1) which it passed on January 15th 2012. Between January 16th and 19th the planet passed to the South of Aquarius' most recognisable feature: the asterism informally known as The Steering Wheel, which is centred on the star Zeta Aquarii (Greek lower-case letter 'zeta' Aqr, mag. +3.6) . On January 28th the planet passed just 2' (about eight apparent Venus-widths) to the South of the star Phi Aquarii (Greek lower-case letter 'phi' Aqr, mag. +4.2), which marks the top of the amphora from which the Water-Bearer figure pours his water.

Star chart showing the paths of Venus and Mercury through Libra, Scorpius, Ophiuchus, Sagittarius and Capricornus from October 2011 to January 2012 (click for full-size star map) (Copyright Martin J Powell 2011)

The Paths of Venus and Mercury through the zodiac constellations during the earlier part of Venus' evening apparition in 2011-12 (the latter part appears in the star chart above). Planet positions are plotted for 0 hrs Universal Time (UT) at 5-day intervals (click thumbnail for the full-size version). For Venus, apparition data for the dates shown in bright white (at 10-day intervals) are included in the table above.

Both evening and morning apparitions of Mercury are included. Wherever a planet is too close to the Sun to view, the path is shown by a dashed line (- -). Hence Mercury's evening apparition drew to a close at the end of November 2011. 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 mid-December for a morning apparition which lasted through to about mid-January 2012. Because Mercury is only ever seen in twilight, many of the fainter stars shown in the planet's vicinity would not have been visible when the planet itself was observed.

Note that most of an inferior planet's retrograde (East to West) motion takes place when it is too close to the Sun to be seen. This is quite unlike the situation for the superior planets, whose period of retrogression is the best time in which to view them.

The positions at which Mercury 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 October-November evening apparition of Mercury favoured Southern hemisphere observers (who should refer to the Southern hemisphere chart for a more appropriate orientation) whilst the morning apparition of December 2011-January 2012 was more favourable for Northern hemisphere observers.

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 and Southern hemisphere 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.

Around mid-January 2012, observers in Southern Tropical latitudes saw Venus reach its highest altitude after sunset. From latitude 25 South, the planet was positioned 21 above the Western horizon (at 30 minutes after sunset) and set two hours after the Sun.

Venus entered Pisces, the Fishes, on February 2nd, crossing the celestial equator (declination = 0) in a Northward direction on February 9th. The following day (February 10th) the planet encountered Uranus, passing 21' (0.35) to the North of the blue-green planet. The separation was easily contained within a low-power telescope eyepiece, however the conjunction had the same problem as that for Neptune only a month earlier: namely, the brilliance of Venus confounding the ease of viewing. In this case the problem was somewhat less since Venus shone at a magnitude of -4.0 whilst Uranus was a more comfortable +5.9.

On February 16th Venus crossed the ecliptic heading Northwards, then on February 19th it passed 2 South of the star Delta Piscium (Greek lower-case letter 'delta' Psc, mag. +4.4). Four days later the planet passed 37' (0.6) South of Epsilon Piscium (Greek lower-case letter 'epsilon' Psc, mag. +4.2). Now approaching Pisces' Eastern border with Aries, the Ram, Venus passed 3.3 North of the fancifully-named star Torcularis Septentrionalis (Greek lower-case letter 'omicron' Psc or Omicron Piscium, mag. +4.2) on March 4th. The planet entered Aries just 7 hours later.

Venus' passage through the small constellation of Aries was an eventful one, involving both a planetary conjunction and a maximum solar elongation. On March 6th 2012 Venus passed 7.4 South of Aries' second-brightest star Sheratan (Greek lower-case letter 'beta' Ari or Beta Arietis, mag. +2.6), then on March 9th it passed 8.7 South of its brightest star Hamal (Greek lower-case letter 'alpha' Ari or Alpha Arietis, mag. +2.0).

On March 15th 2012, Venus passed the bright planet Jupiter in a spectacular planetary conjunction which was easily the best of Venus' 2011-12 apparition. The conjunction was well-placed for Northern hemisphere observers in particular. Jupiter, which had been dominating this region of the sky for several months, was now magnitude -1.9 (having faded somewhat since its opposition in the previous October) and was positioned 3.3 to the South of Venus (which had now brightened to mag. -4.2). When assessed in terms of visual impact and ease of viewing, the March 2012 Venus-Jupiter conjunction was the best to take place between any of the planets until mid-2015.

Around mid- to late March, observers in Equatorial latitudes saw Venus attain its highest altitude above the local horizon for the 2011-12 apparition, the planet being some 31 high in the West-North-west at 30 minutes after sunset (the scenario is shown in the form of a horizon diagram below). At these latitudes, the planet now remained visible for almost three hours after sunset.

On March 25th 2012 Venus passed 1.2 North of the star Botein (Greek lower-case letter 'delta' Ari or Delta Arietis, mag. +4.3), the Easternmost star of the Ram figure. Venus reached its greatest elongation from the Sun for this apparition (46.03 East) on March 27th 2012, when it was positioned about 2.3 to the North-east of Botein. At this stage, telescopes showed Venus' disk half-illuminated (phase = 0.50 or 50%) with an apparent diameter of  23".5. Although the greatest elongation from the Sun occurred on March 27th, Venus was in fact positioned at precisely 46.0 elongation for a ten-day period from March 22nd through to April 1st.

For a few days around greatest elongation, telescopic observers often look to find the precise moment when the terminator (the line seperating 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. This anomaly is known as Schrter's Effect and it is well-known amongst telescopic observers of the planet.

For Northern hemisphere observers, the date of Venus' maximum solar elongation in 2012 was ideal, since it coincided with the period during which the planet attained its highest position above the local horizon after sunset. From late March into early April of 2012, for example, observers at latitude 30 North saw the planet attain a significant 38 above the local horizon at 30 minutes after sunset - the highest altitude attained from any latitude during the 2011-12 apparition. Higher latitudes did not fare much worse. Even from latitude 60 North, in late March 2012, the planet was placed 32 above the local horizon at 30 minutes after sunset. This ideal set of circumstances meant that Venus remained visible after sunset for between 3 hours (at 30 North) and 5 hours (at 60 North)!

For the naked-eye planet observer situated at mid- and high-Northern latitudes, Venus' 2011-12 apparition was the best evening apparition in the planet's apparition 'cycle' (there being five evening and five morning apparitions in each Venusian 8-year 'cycle'). For Equatorial and Southern hemisphere observers, it was the worst evening apparition in the 'cycle'. For telescopic observers of the planet, however, the relatively high placement of Venus in the sky after sunset 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.

Venus entered Taurus, the Bull, on March 30th 2012, where it remained through to the end of the 2011-12 apparition. On April 3rd the planet passed South of the open star cluster known as the Pleiades (pronounced 'PLY-add-eez' or 'PLEE-add-eez'), designated Messier 45 (M45) by the French astronomer Charles Messier (1730-1817) who published his first catalogue of nebulous objects in 1774. Also known by the name The Seven Sisters, they are probably the best-known star cluster in the night sky. Under dark skies the seven brightest stars in the group can be seen with the naked-eye; they are Alcyone (Greek lower-case letter 'eta' Tauri or Eta Tauri, mag. +2.9), Atlas (mag. +3.6), Electra (mag. +3.7), Merope (mag. +4.2), Taygete (mag. +4.3), Pleione (mag. +5.1v) and Celaeno (mag. +5.5). Venus took a little over a day to traverse the apparent width of the Pleiades, passing 35' (0.6) South of Electra (the Westernmost naked-eye star of the group) on April 3rd and then 14' (0.2) South of Atlas (the Easternmost naked-eye star of the group) on April 4th.

From April 12th to April 17th 2012 Venus passed to the North of the large V-shaped star cluster known as the Hyades. Although an obvious cluster to the naked eye, Charles Messier did not include it in his catalogue (he was looking for objects which could be confused with comets - and the Hyades certainly do not look like a comet!) The cluster comprises around 200 stars spread over an exceptionally large area of about 5 of the sky. Although it does not have a Messier number, the Hyades do have other catalogue references, namely Melotte 25, Collinder 50 and Caldwell 41 (the latter being the most recent, catalogued by the British astronomy-writer and TV presenter Sir Patrick Moore in 1995).

On April 12th, Venus passed 10.1 North of the Hyades' Westernmost star Hyadum Primus (Greek lower-case letter 'gamma' Tauri, mag. +3.6) which is positioned at the vertex of the 'V'-shape. On April 17th the planet passed 10 North of Taurus' brightest star Aldebaran (Greek lower-case letter 'alpha' Tauri, mag. +0.9). Aldebaran is a red giant star which appears as the Easternmost star of the cluster but in fact, it is not a physical member of the Hyades group; its appearance in the cluster is purely a line-of-sight effect. The Hyades lie at a distance of about 150 light years from Earth (where 1 light year = 63,240 Astronomical Units), whereas Aldebaran is much closer, at 68 light years.

As Venus proceeded towards the North-eastern corner of Taurus, its apparent motion against the background stars was slowing. When it entered Taurus in late March 2012 its apparent motion was about 1 per day but by the close of April its apparent daily motion had slowed to 0.5. The solar elongation was also narrowing, having reduced from 46 in late March to around 40 in late April. Since greatest elongation day Venus had been showing a crescent phase through telescopes, its apparent size slowly enlarging with each passing day.

The planet attained its greatest brilliancy for this apparition (mag. -4.4) on April 30th 2012. 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 2012 this took place when the planet was 27% illuminated (phase = 0.27), its angular diameter was 37".4 and its solar elongation was 39.8. Thirty minutes after sunset, naked-eye observers in the Northern hemisphere now saw Venus in its true majestic brilliance against a dark sky, positioned some 30 high above the Western horizon. For much of the Southern hemisphere, Venus was brilliant and the sky was dark, but the planet was less than 20 above the horizon at 30 minutes after sunset.

On May 4th Venus attained its most Northerly declination for this apparition (+27.82) which is the most Northerly declination attained by the planet during both 20th and 21st centuries! The planet was now 4.7 North of the ecliptic (ecliptic latitude = +4.7) and only 51' (0.85) South of Taurus' boundary with Auriga, the Charioteer. Across the world, the planet now set at its most Northerly point along the local horizon.

Venus passed 48' (0.8) South of the star Nath (Greek lower-case letter 'beta' Tau or Beta Tauri, mag. +1.7) on May 7th. Nath (also spelled Alnath or El Nath) marks the tip of the Bull's Northern horn, but it is also shared by Auriga, the Charioteer, being its most Southerly star. The planet's apparent motion continued to slow until, on May 15th, its Eastward motion ceased when it reached its Eastern stationary point, 1.8 to the South-east of Nath. Thereafter Venus moved retrograde (East to West) against the background stars, its declination (and ecliptic latitude) reducing as it accelerated towards the close of its 2011-12 apparition. The planet passed 2.4 South of Nath on May 23rd, an event which was difficult to view from high-Southern latitudes because of Venus' low altitude after sunset.

From around mid-May 2012, steadily-held binoculars began to detect Venus as a tiny crescent soon after sunset as the planet languished low in the West-North-western sky. Telescopes showed a large, thin crescent at this point, nearly 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). Its solar elongation now having reduced below 30, observers at mid-Southern latitudes began to have some difficulty viewing Venus as it sank into the bright dusk twilight.

As the Venusian crescent continued to enlarge it also becomes more slender, such 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 until recently had no clear explanation. Given the extremely high temperatures which are known to exist beneath the Venusian clouds, the Ashen Light is today considered by many to be a visual indication of the planet's surface glowing red hot.

In late May, observers with exceptionally-good eyesight may have attempted to observe the crescent of Venus with the naked-eye. Whilst this may seem extraordinary, the planet's apparent size of around 58" brings it very close to the generally-accepted resolution of the human eye, i.e. 1 arcminute. Because the planet's solar elongation was then around 15 or less, glare was no longer a problem because the planet was then seen in bright twilight through to its setting, theoretically allowing the crescent to be discerned more easily.

By early June, Venus became lost from view from all locations as it sped towards inferior conjunction (passing between the Earth and the Sun) on June 6th 2012. Under normal circumstances this would mark the end of the planet's evening apparition, however in 2012 (as in 2004) the spectacle was not yet over; indeed, the highlight of the apparition was about to take place. For on June 5th-6th 2012, viewed from the Earth, Venus was seen as a tiny black dot moving across the Sun's disk in a very rare event called a transit of Venus; for more details, see the 'Transit of Venus 2012' page.

After Venus' solar transit, the planet was once again lost from view, having passed from the evening to the morning sky. The period of non-visibility was brief, however; from mid-June 2012, Venus was seen rising as a 'Morning Star' in the Eastern sky shortly before the Sun, heralding a new morning apparition (2012-13) which lasted through to February 2013.

 [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 in 2012

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 conjunction or an appulse. However, not all conjunctions will be visible from the Earth because many of them take place too close to the Sun. Furthermore, not all conjunctions 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.

 Simulation of a conjunction between Venus and Jupiter on March 15th 2012, seen over Liberty Island, New York City (based on a photograph by 'Lars0001' at Panoramio.com)

A conjunction of Venus and Jupiter as it might have appeared over Liberty Island on the evening of March 15th 2012. Venus is the uppermost and brighter of the two planets. This is the author's simulation of the event, based on a photograph by 'Lars0001' at Panoramio.com.

Conjunctions are generally considered most noteworthy when they involve two bright planets, and no planetary conjunction is more spectacular than those involving Venus. During the course of one Earth year, Venus is seen to complete over 1 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). In 2011, for example, Venus and Saturn were technically in conjunction on September 30th, when they were about 12 East of the Sun. Whilst Venus was then an easy naked-eye object after sunset (shining at an apparent magnitude of -3.8), Saturn (at mag. +1.0) was much more distant and almost five magnitudes fainter than Venus so that it was near-impossible to detect in the bright evening twilight glow. Owing to the difficulty in viewing it, this conjunction is not included in the table below.

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). Conjunctions between Venus and Jupiter are arguably the most spectacular to view, Venus always being the brighter of the two. The conjunction of March 15th 2012 was easily the best of the 2011-12 apparition, both planets being positioned high in the Western sky after sunset.

Uranus and Neptune are rather more tricky objects to observe whenever they are involved in conjunctions with Venus, because Uranus is only just visible to the naked eye and Neptune never reaches naked-eye visibility. Twilight quickly renders these two planets invisible (even through binoculars), so conjunctions taking place less than about 20 from the Sun will be difficult or impossible to see. Even when the elongation is favourable, a further problem beckons in that the glare caused by Venus' brilliance makes it difficult to see the much fainter planet beside it. In such instances (e.g. for the Venus-Uranus conjunction of February 10th 2012) binocular observers may find it easier to position Venus just outside the binocular field of view so that the eye can more comfortably view the distant gas giant.

Conjunctions between Venus and Mercury 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 will often be difficult to see because of their narrow solar elongation. There were no visible conjunctions during the 2011-12 apparition, however there was an interesting 'near miss' on 9th November 2011, when the two planets were some 22 East of the Sun on the Scorpius/Ophiuchus border. On this day, Mercury approached Venus to within just 0.2 of celestial longitude and 2 in celestial latitude but they did not conjunct. In fact, the planets appeared to move almost parallel to each other for several days from around 7th to 11th November before drifting apart when Mercury's apparent motion slowed before reaching its Eastern stationary point. Since no conjunction occurred during this period, this event is excluded from the table below.

Only three planetary conjunctions with Venus were viewable during the 2011-12 apparition and these are listed in the table below.

Table showing the visible Venus conjunctions with other planets during the evening apparition of 2012 (Copyright Martin J Powell, 2011)

Venus conjunctions with other planets during 2012 (there were no visible conjunctions during the evening apparition in 2011). 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 2012 Mar 15, Jupiter was positioned 3.3 South 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 45N 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 Dawn/Morning visibility and Dusk/Evening visibility; the terms Dawn/Dusk refer specifically to the twilight period before sunrise/after sunset, whilst the terms Evening/Morning refer to the period after darkness falls/before twilight begins (some conjunctions take place in darkness, others do not, depending upon latitude). The 'Con' column shows the constellation in which the planets 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 are located ('Con' column) on the required date and find the constellation's rising direction (for Dawn/Morning apparitions) or setting direction (for Dusk/Evening apparitions) for your particular latitude in the Rise-Set direction table.

The table is excerpted from another showing Venus conjunctions with other planets from 2010 to 2015 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 23 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, September 2011 to May 2012

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 September 2011 and May 2012:

Date Range

(World)

Conjunction (Geocentric)

Solar Elong.

Moon Phase

Date & Time

Sep. & Dir.

2011

Sep 27/28

Sep 28, 10:19 UT

5.7 N

11E

Waxing Crescent

throughout

Oct 27/28

Oct 28, 05:10 UT

1.8 N

19E

Nov 26/27

Nov 27, 04:28 UT

2.8 S

26E

Dec 26/27

Dec 27, 11h UT

6.5 S

33E

2012

Jan 26/27

Jan 26, 18h UT

6.8 S

39E

Waxing Crescent

throughout

Feb 25/26

Feb 25, 21:43 UT

3.3 S

44E

Mar 26/27

Mar 26, 18:21 UT

1.8 N

46E

Apr 24/25

Apr 25, 02:22 UT

5.7 N

42E

May 22/23

May 22, 20:53 UT

4.7 N

21E

Moon near Venus dates for the evening apparition of 2011-12. 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 were 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 February 25th 2012 at 21:43 UT, Venus was positioned 3.3 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 Moon moves relatively quickly against the background stars (in an Eastward direction, at about its own angular width [0.5] each hour, or about 12.2 per day) and 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 could 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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Direction, Altitude & Visibility Duration of Venus after Sunset, September 2011 to May 2012

The following tables give the direction and altitude (angle above the horizon) of Venus at 30 minutes after sunset, together with the visibility duration of the planet after sunset, for the 2011-12 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 2011-12 evening apparition, and in which direction it was seen. For example, observers situated at latitude 40 North (a mid-Northern latitude) found the planet highest in the sky (at 30 minutes after sunset) in late March 2012, when it was seen at an altitude of 37 towards the West. The duration column shows that the planet was then above the horizon for about 4 hours after sunset.

Northern Hemisphere Latitudes

Table showing direction & altitude (30 minutes after local sunset) and visible duration of Venus for Northern hemisphere latitudes for the 2011-12 evening apparition (Copyright Martin J Powell 2011)

Direction & Altitude (30 minutes after local sunset) and Visibility Duration of Venus for Northern hemisphere latitudes and the Equator for the evening apparition of 2011-12. To find your latitude, visit the Heavens Above website, select your country and enter the name of your nearest town or city using the 'Town Search' facility.

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 is seen under twilight conditions through to its setting, i.e. it is 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 letter 'D' indicates that Venus sets 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 sets 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 sets on any given date for a particular latitude, note down the constellation in which the planet is located on the required date (column headed Con) then find its setting direction for your latitude in the Rise-Set direction table.

Southern Hemisphere Latitudes

Table showing direction & altitude (30 minutes after local sunset) and visible duration of Venus for Southern hemisphere latitudes for the 2011-12 evening apparition (Copyright Martin J Powell 2011)

Direction & Altitude (30 minutes after local sunset) and Visibility Duration of Venus for Southern hemisphere latitudes and the Equator for the evening apparition of 2011-12. The column headings are described under the Northern hemisphere table above.

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Direction & Altitude Diagrams (Horizon Diagrams) for the 2011-12 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 2011-12 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.

For higher accuracy, the azimuth (the bearing measured clockwise from True North) is also shown along the direction axis. For each of the latitudes shown, the direction and altitude of Venus after sunset can be estimated for any part of the 2011-12 evening apparition by positioning your pointing device over each image, when an overlay grid will appear, marked at 10 intervals; the values can then be read off accordingly.

 

Path of Venus in the evening sky during 2011-12, seen from latitude 55 North (Copyright Martin J Powell 2011)

The Path of Venus in the Evening Sky (plotted for 30 mins after sunset) during 2011-12 for an observer at latitude 55 North.

Path of Venus in the evening sky during 2011-12, seen from latitude 35 North (Copyright Martin J Powell 2011)

The Path of Venus in the Evening Sky (plotted for 30 mins after sunset) during 2011-12 for an observer at latitude 35 North.

Path of Venus in the evening sky during 2011-12, seen from the Equator (Copyright Martin J Powell 2011)

The Path of Venus in the Evening Sky (plotted for 30 mins after sunset) during 2011-12 for an observer at the Equator (latitude 0).

Path of Venus in the evening sky during 2011-12, seen from latitude 30 South (Copyright Martin J Powell 2011)

The Path of Venus in the Evening Sky (plotted for 30 mins after sunset) during 2011-12 for an observer at latitude 30 South.

Paths of Venus in the Evening Sky (30 mins after sunset) for the 2011-12 evening apparition, as seen by observers at latitudes 55 North, 35 North, the Equator and 30 South. 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). 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, move your pointing device over each image (or click on the picture) to see an overlay grid marked at 10 intervals in azimuth and altitude (the dates are removed for clarity). For example, at latitude 35 North on February 1st 2012, at 30 minutes after sunset, Venus was found at azimuth = 239 (i.e. in the WSW) and altitude = 30.

Although the dates indicated in the above diagrams refer specifically to the period 2011-12, Venus has an 8-year cycle of apparitions such that its position in the evening sky in 2011-12 will repeat very closely in the evening sky of 2019-20. The author refers to this particular evening apparition as Apparition C1; for more details, see the accompanying article describing The Venus 8-year Cycle.

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Naked-eye Venus: Apparitions, Conjunctions and Elongations, 2010-2020

The Naked-eye appearance of Venus

Naked Eye Planet Index

Planetary Movements through the Zodiac

 

Mercury

Venus

Mars

Jupiter

Saturn

Uranus

Neptune

Pluto


 

Credits

 


Copyright  Martin J Powell  October 2011; revised January 2012, June 2012.


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