Visibility of the planets from New Zealand in 2012

Mercury is last at inferior conjunction in 2011 on December 4. Following inferior conjunctions it becomes a morning object. Thus it is in the morning sky from December 4 until 2012 February 7. The planet is again in the morning sky between March 22 and May 27, between July 28 and September 10 and from November 17 until 2013 January 18.

The best morning appearance of Mercury will be in April, when the planet will rise more than 2 hours before the Sun from about the 10th to the first week in May. Mercury is brighter in May than in April . The January morning apparition is poorer, at best Mercury rises some 80 minutes before the Sun. At the other two morning apparitions in August and December, Mercury will rise less than an hour before the Sun so is likely to be too low in the morning twiligh to see.

Mercury becomes an evening object after each superior conjunction. The dates of it being in the evening sky for 2012 are February 7 to March 22, May 27 to July 28, and September 10 to November 17. During the February and March apparition the planet sets, at most, only just over half an hour after the Sun, so will not be visible. At the other two the planet will set just over 2 hours after the Sun, in the first week of July and again in the second half of October. During both Mercury will be briefly visible in the dusk sky. Mercury is brightest at the start of the period of evening appearances of the planet.

For northern hemisphere observers the best evening apparitions are in early March and late June. The best morning apparition is at the beginning of December.

Mercury and Saturn are in conjunction on October 5. Mercury will be the brighter at magnitude -0.3. The two are likely to be visible low to the west some time after sunset.

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Venus starts the year as an evening object setting 2 hours after the Sun at the beginning of January. During the following months it will gradually set earlier and so become lower in the evening sky but will remain visible after sunset. It is likely to be late May before the planet is too close to the Sun to see.

On June 6 Venus is at inferior conjunction between the Sun and Earth. At this conjunction the planet will transit across the northern part of the Sun. The entire transit is nominally visible from New Zealand although few places are likely to see the end which occurs very close to the time of sunset so that the Sun and planet will very low.

Before the transit in mid March, Venus and Jupiter will be in conjunction. The two are closest on the evening of March 14 when Venus will be 3° below Jupiter. The two are quite close for several evenings either side of the date. Half an hour after sunset Venus will be some 8° above the horizon.

After the transit Venus will move rapidly into the morning sky. Just over fortnight later it will rise 2 hours before the Sun and more then 3 hours earlier during the last 3 weeks of July and early August. When Venus is first visible towards the end of June it will again be a few degrees below Jupiter in the dawn sky. By the end of June the two planets will be nearly level, with Venus just under 5° to the right of Jupiter. They will be in Taurus between the Pleiades and Aldebaran. During July the two planets will remain fairly close with Venus gradually moving a little further from and down from Jupiter.

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Mars will rise shortly after midnight at the beginning of the year. It is at opposition March 3 when it will rise close to the time of sunset and set at sunrise, so being visible all night. At the 2012 opposition, Mars will be close to aphelion, 1.66 Au from the Sun, so this will not be a bright event. Even so its magnitude will be a healthy -1.2, brighter than all stars except Sirius.

Mars will remain an evening object throughout the rest of 2012. By the end of December it will set about 90 minutes after then Sun. By then it will be at magnitude 1.2.

Mars and Saturn are in conjunction in mid August, the two being closest on August 15. This is probably the best planetary conjunction of the year. Mars, magnitude 1.1, will be 2.7° from Saturn, magnitude 0.8. While Saturn will be to the right of Mars, the star Spica magnitude 1.06, will be 1.8° to the left of Mars. The best line up of the three will be on the evening of August 14.

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Jupiter is in Pisces for the first 9 days of January after which it moves into Aries. On May 14 the planet moves on into Taurus where it stays for the rest of the year.

The planet is at conjunction with the Sun on May 13 and at opposition on December 3. Consequently it will be an early evening object during the first part of the year, becoming lost to view in the sunset glow during April. After conjunction Jupiter becomes a morning object although it is not likely to be visible before about mid June. It will be to the east in the dawn sky. By mid November Jupiter will again be visible in the late evening.

The planet is stationary on October 4 and will then start moving in a retrograde, westerly, direction. It will continue moving in this sense until the end of January 2013.

In mid March Jupiter is in conjunction with Venus when the two planets will be 3° apart and visible in th early evening sky. They are close again at the end of June and early July, now as morning objects.

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Saturn is in Virgo during 2012 until it moves into Libra on December 7. It starts the year as a morning object rising near and 2 am NZDT in most of New Zealand. It will become visible in the late evening sky towards the end of February. Saturn reaches opposition on April 16 (NZDT). By then it will rise at about the time the Sun sets and be in the sky all night.

The planet is first stationary on February 8 after which it moves in a retrograde direction to the west. It is stationary for a second time on June 16 when it will recommence moving to the east. Saturn is close to Spica for much of 2012. The distance between them reaches a minimum on two occasions. In mid May the two will be 4.8° apart while Saturn is retrograding. Then after being stationary Saturn moves forward again to pass Spica early in August when their separation will be slightly less, just under 4.5°. Slightly later in mid August, Mars will lie between Spica and Saturn.

During 2012 the northern face rings of Saturn's rings will become noticeably more exposed to view particularly by the end of the year.

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Uranus is in Pisces at the beginning and end of 2012. On May 12 it starts crossing a corner of Cetus. It gets almost right across the corner (to take it back into Pisces) when the planet reaches its first stationary point on July 13. It then reveres its direction of motion to take it back into Pisces on September 16, very close to where it left the constellation. Uranus is stationary again on December 13, after which it will start moving forward again towards the corner of Cetus which it crosses completely in 2013.

Uranus is at conjunction with the Sun on March 24. After this Uranus will be a morning object rising before the Sun. Opposition is just over 6 months later on September 29.

A close conjunction of Venus and Uranus occurs on February 10 when Uranus will be less than half a degree to the upper left of Venus. This will be visible in the evening sky, but only some 6.5° above the horizon one hour after sunset.

Neptune is in Aquarius throughout 2012. It starts the year as an evening object setting shortly before midnight. By the end of January it will set only an hour after the Sun and so become lost to view. The planet is at conjunction with the Sun on February 19 after which it becomes a morning object, rising before the Sun.

Neptune is stationary on June 5, and reaches opposition on August 24 by which time it will again be visible in the evening sky. The planet is stationary a second time on November 11.

Further details of Uranus and Neptune in 2012.

Pluto is in Sagittarius during 2012. It is in conjunction with the Sun at the end of 2011, on December 29 so will become a morning object in the New Year. Opposition is on June 29 and the planet returns to solar conjunction on December 30. The planet is stationary on April 10 and again on September 17. It moves in a retrograde sense between these dates

Planetary conjunctions during 2012

The table shows all the conjunctions of planets which occur during 2012, except those for which the planets are too close to the Sun to observe. The minimum separations are shown in degrees. The diameter of the full moon is about half a degree. Dates are as in New Zealand, for morning events the UT date is one less.

All of the conjunctions involve either Mercury or Venus except for one. As a result they will be fairly low in the sky either in the evening shortly after sunset, or in the morning shortly before sunrise. Altitudes are given for a time when the brighter planet should be easily visible to the unaided eye although the fainter planet may need binoculars to see.

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Sky charts for some of the conjunctions

Venus and Jupiter between Aldebaran and the Pleiades, July 1

The chart the positions of Venus and Jupiter between Aldebaran and the Pleiades in Taurus on the morning of July 1. This is the date when the planets are closest, 4.8° apart, in the morning sky. It is not a true conjunction as the planets are never at the same longitude

The circle represents a field 5° in diameter, the typical field of view for binoculars. The view shows the orientation of the planets and stars as seen from mid southern latitudes about 50 minutes before sunrise. This will be at or just before 7 am in the North Island, but some time after 7 am in the South, near to 7.45 am at Invercargill.

The planets will be to the northeast about 16° above the horizon. Stars to 5.0 are shown. With the Sun barely 10° below the horizon, there will already be a considerable sky glow to the northeast which may make the Pleiades difficult to see. So a better view is likely a little earlier - but this part of the sky will then be lower.

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Paths of Mars and Saturn near conjunction August 15

The chart shows the paths of Mars and Saturn between August 5 and 25, at the time Mars passes Spica. Daily positions of Mars are indicated, while the position of Saturn is shown for 5, 15 and 25 of August. The two planets are marked at their position on August 15 when they are closest. The best line-up with Spica is the previous night, August 14.

The circle represents a field 5° in diameter, the typical field of view for binoculars. The view shows the sky as seen from mid southern latitudes about 2 hours after sunset and 3 hours before the planets set. Stars brighter than magnitude 5.5 are shown. These should be visible to the unaided in a dark, moonless, sky. The magnitudes of the two brightest are shown with a decimal point.

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