The Solar System in May 2016

Dates and times shown are NZST (UT + 12 hours) unless otherwise stated.

Rise and set times are for Wellington. They will vary by a few minutes elsewhere in NZ.

Sunrise, sunset and twilight times in May

                            May  1  NZST                     May 31  NZST
                    morning  evening                 morning  evening
       SUN: rise:   7.05am,  set:  5.29pm    rise:   7.33am,  set:  5.03pm
Twilights
  Civil:    starts: 6.39am,  ends: 5.56pm    starts: 7.05am,  ends: 5.31pm
  Nautical: starts: 6.07am,  ends: 6.29pm    starts: 6.31am,  ends: 6.06pm
  Astro:    starts: 5.34am,  ends: 7.01pm    starts: 5.58am,  ends: 6.39pm

May PHASES OF THE MOON (times as shown by GUIDE)

          New moon:      May  7 at  7.30 am (May  6, 19:30 UT)
  First quarter: May 14 at  5.02 am (May 13, 17:02 UT)
  Full moon:     May 22 at  9.14 am (May 21, 21:14 UT)
  Last quarter   May 30 at 12.12 am (May 29, 12:12 UT)

The planets in May

Mercury is at inferior conjunction on May 9 when it will transit the Sun, an event visible from the opposite side of the Earth to NZ. After conjunction Mercury becomes a morning object and will be readily visible towards the end of May. Mars is at opposition on May 22 when it will be as bright as Jupiter. Mars will be close to Antares and Saturn.

Mercury starts May as an evening object, but sets only 24 minutes after the Sun on the 1st, so is not observable. It is at inferior conjunction between the Earth and Sun on the morning of May 10 NZST.

At the May conjunction Mercury will transit the Sun. The transit starts at 11:12 pm on 9 May (NZST) and ending at 6:42 am on 10 May (NZST); UT date and times are May 9, 11:12:18 and 18:42:14 respectively. The end is about half an hour before sunrise at Wellington. Thus the transit is not visible from New Zealand nor from Australia. The Middle East, Europe and Africa are well placed for viewing the start of the transit, the later stages are visible from the Americas. Apart from much of the Atlantic Ocean, Greenland and Brazil are the best places for seeing the entire event.

After conjunction Mercury becomes a morning object moving away from the Sun fairly rapidly. By May 24 the planet, at magnitude 1.8 will be some 7.5° above the horizon an hour before sunrise. A week later Mercury, now magnitude 1.0, will be nearly 10° up an hour before sunrise. Look for Mercury in a direction about 25° north of east.

Venus, in the morning sky, is close to the Sun all month. At the start of May its elongation is 10° with the planet rising 50 minutes before the Sun. By the 31st it will rise only 9 minutes before the Sun. So viewing is going to be difficult.

Mars, which has been steadily brightening recently, is at opposition on May 22. At magnitude -2.1 it will briefly be as bright as Jupiter. Mars will be close to Antares, the two just under 9° apart. The star at magnitude 1.1 is looking almost dim compared to the planet. Saturn will be about 12° from Mars and on the evening of May 22, the just past full moon will be 9° distant.

Mars is closest in its orbit to the Earth on May 31 when the two will be just over 75 million kilometres apart.

Jupiter will be best placed for viewing early evening, although it doesn’t set until after midnight. The planet is in Leo, its position changes little during the month, being stationary on May 10.

The 66% lit moon will be just over a degree from Jupiter on May 15.

Saturn rises an hour and three quarter after the Sun sets on May 1, and just 6 minutes after sunset on the 31st. So it is best viewed later evening. The planet, in Ophiuchus, is a few degrees from Antares. Saturn’s magnitude brightens from 0.2 to 0.0 during the month.

The moon passes Saturn on the 22nd but will be closest well after they set in NZ. The two are about 7° apart on the evening of May 22 and about 7.5° apart the following evening with the moon the opposite side of Saturn.

Outer planets

Uranus is a morning object in Pisces at magnitude 5.9. It rises about 100 minutes before the Sun on the 1st increasing to 4 hours earlier on the 31st.

Neptune is in the morning sky, rising just after midnight by May 31. The planet, at magnitude 7.9 is in Aquarius. Neptune is moving to the east past the 3.7 magnitude star lambda Aqr. The two are closest mid month when less than half a degree apart. Neptune will be to the upper right of the star. No stars as bright as Neptune are between the two.

Pluto at magnitude 14.4 rises close to 9.30 at the start of May and 2 hours earlier by the end of the month. The planet remains in Sagittarius less than 1° from the 2.9 magnitude star pi Sgr.

Minor planets

(1) Ceres, magnitude 9.3, is in Cetus during May. It rises just before 4 am on the 1st and just over an hour earlier by the 31st.

(4) Vesta, magnitude 8.4, is in Taurus. Its starts May as an evening object setting less than an hour after the Sun. It is at conjunction with the Sun on the 24th when the two will appear about 3.5° apart.

(7) Iris is at opposition on May 29 with a magnitude 9.2. The asteroid will be in Ophiuchus, 3° from Antares, just under 6° from Saturn and 9.5° from Mars. The 5th magnitude star rho Oph will be just over 13 arc minutes from Iris. The star has two close companions easily visible in binoculars at magnitudes 6.8 and 7.3, each about 2.5 arc minutes from brighter star.

Brian Loader  
New Zealand

The solar system in April 2016

NZDT ends on Sunday April 3 at 3am, clocks should then be set back one hour. Dates and times shown are NZDT (UT + 13 Hours) up to the change and then as NZST (UT + 12 hours) unless otherwise stated.

Rise and set times are for Wellington. They will vary by a few minutes elsewhere in NZ.

Sunrise, sunset and twilight times in April

                            April  1  NZDT                   April 30  NZST
                    morning  evening                 morning  evening
       SUN: rise:   7.34am,  set:  7.14pm    rise:   7.04am,  set:  5.30pm
Twilights
  Civil:    starts: 7.09am,  ends: 7.40pm    starts: 6.38am,  ends: 5.57pm
  Nautical: starts: 6.37am,  ends: 8.12pm    starts: 6.06am,  ends: 6.30pm 
  Astro:    starts: 6.05am,  ends: 8.44pm    starts: 5.33am,  ends: 7.02pm

April PHASES OF THE MOON (times as shown by GUIDE)

          Last quarter:  April  1 at  4.17 am (Mar 31, 15:17 UT)
  New moon:      April  7 at 11.24 pm (11:24 UT)
  First quarter: April 14 at  3.59 pm (03:59 UT) 
  Full moon:     April 22 at  5.24 pm (05:24 UT) 
  Last quarter   April 30 at  3.29 pm (03:26 UT)

The planets in April

Jupiter will dominate the evening sky particularly early and late in the month when the moon is absent. Mercury is likely to be lost in evening twilight, setting soon after the Sun. Mars and Saturn will be to the east later in the evening, with Mars brightening to magnitude -1.5 during the month. Venus is rather low in the dawn sky.

Mercury is nominally in the evening sky in April but virtually unobservable. On the 1st it sets about 20 minutes later than the Sun, on the 30th about 26 minutes later. At its greatest, mid month, when the planet is at its greatest elongation 20 ° east of the Sun, it sets later.

Venus is a low object in the morning sky in April. On the 1st it will be about 16° up as the Sun rises just north of east. By the end of the month it will be only 8.5° at sunrise, so a low but not impossible object to spot shortly before the Sun appears.

Uranus will be less than a degree to the lower left of Venus on the morning of the 23rd, but with a magnitude of 5.9 it is very doubtful the fainter planet will be visible in binoculars in the twilight.

The moon, as a very thin crescent, will be 7° above Venus on the morning of the 6th, the following morning the moon will be a similar distance below Venus. As a hair line crescent, less than 1% lit, the moon will be very difficult to spot.

Mars brightens during April by a magnitude from -0.5 to -1.5 as its distance from the Earth decreases leading up to its opposition in May. The planet rises at 9.40 pm (NZDT) on the 1st and 6.40 pm (NZST) on the 30th so by then is visible most of the night.

The planet starts April in Scorpius, 6° from Antares. It crosses into Ophiuchus on the 3rd when it will be some 8.5° from Saturn. But on the 17th Mars is stationary and then starts moving back to the west to cross back into Scorpius on the last day of the month. As a result it remains quite close to the similarly coloured Antares all month.

The moon, just past full, is closest to Mars on the 25th, when Mars, Saturn and the moon will form a near equilateral triangle with Mars at the upper apex.

Jupiter, having been at opposition early March, will be a prominent evening object throughout April. It will be in Leo moving slowly to the west towards Regulus, with the star 15° to the left of the planet as seen in the evening sky.

The moon and Jupiter will be closest on June 18, when the 87% lit moon will be about 3° from Jupiter mid evening.

Saturn will rise about 10.15 pm on the 1st, advancing to 7.20 pm on the 30th. It will not set until after sunrise. The planet remains in Ophiuchus heading slowly to the west towards Mars. The two are closest mid month when about 7° apart.

As noted for Mars, the moon will form a triple with the two planets on the evening of the 25th. In fact the moon is closest to Saturn on the morning of the 26th with the two 4° apart shortly before sunrise.

Outer planets

Uranus is at conjunction on the far side of the Sun on April 9, so will not be observable during April. At conjunction Uranus will be 20 arc-minutes south of the Sun's limb. Distance wise it will be 20.0 AU from the Sun and 21 AU (3137 million km) from the Earth.

By the end of April Uranus will rise 90 minutes before the Sun and will be 8° above Venus. The two are closest on the morning of April 23.

Neptune, in the morning sky, starts April some 8° above and a little to the left of Venus. By the end of the month the two will be about 50° apart, due to the rapid motion of the inner planet. Neptune will then rise close to 2 am.

On the morning of April 5, Neptune will be 3.5° to the lower right of the crescent moon.

Pluto at magnitude 14.4 rises just after midnight at the beginning of April and about 9.35 pm on the 30th. The planet remains in Sagittarius. It is stationary on April 18 and is about 1° from the 2.9 magnitude star pi Sgr.

Minor planets

(1) Ceres, magnitude 9.2, starts April in Aquarius just under 7° to the right of Venus in the dawn sky. It crosses into Cetus on the 2nd where it soon falls behind Venus. This in fact means it gets steadily higher in the morning sky and will rise at 4 am by April 30.

(4) Vesta, magnitude 8.4, is in Aries until the 30th when it moves into Taurus. It sets 90 minutes after the Sun on the 1st, less than an hour later on the 30th.

The 5% lit crescent moon will be just over 1° to the right of Vesta on April 9. At 6.30 pm the two will be 8° above the horizon as seen from Wellington. Vesta will be about level with the upper lit cusp of the moon.

Brian Loader  
New Zealand