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

The solar system in March 2016

Dates and times shown are NZDT (UT + 13 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 March

                        March  1  NZDT                   March 31  NZDT
                    morning  evening                 morning  evening
       SUN: rise:   6.59am,  set:  8.06pm    rise:   7.33am,  set:  7.16pm
Twilights
  Civil:    starts: 6.34am,  ends: 8.32pm    starts: 7.09am,  ends: 7.42pm
  Nautical: starts: 6.00am,  ends: 9.06pm    starts: 6.36am,  ends: 8.17pm 
  Astro:    starts: 5.25am,  ends: 9.41pm    starts: 6.03am,  ends: 8.46pm

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

          Last quarter:  March  2 at 12.11 pm (Mar  1, 23:11 UT)
  New moon:      March  9 at  2.55 pm (01:55 UT)
  First quarter: March 16 at  6.03 am (Mar 15, 17:03 UT) 
  Full moon:     March 24 at  1.01 am (Mar 23, 12:01 UT) 
  Last quarter   April  1 at  4.17 am (Mar 31, 15:17 UT)

ECLIPSES in March

March 9: Total eclipse of the Sun. The path of totality crosses southern Sumatra soon after sunrise then crosses southern Borneo and the Celebes. It then heads east and northeast across the Pacific to end at sunset to the north of Hawaii. The maximum length of totality is 4 minutes 9 seconds. A partial eclipse is visible from most of southeast Asia including Japan and from most of Alaska. In the south a partial eclipse is visible from Australia except the south and southeast. A map showing the path is available on the RASNZ web site.

March 23/24: A partial penumbral eclipse of the moon. At maximum only part of the moon passes into the penumbra of the Earth's shadow. No part is totally eclipsed. The decrease in brightness of the moon will be small and it is unlikely any change will be noticed by eye. The eclipse starts at 10.39 pm NZDT, maximum eclipse is at 12.47 am, the eclipse ends at 2.55 am NZDT. The moon is visible throughout the eclipse in New Zealand and in Australia except the start in Western Australia.

The planets in March

Jupiter is at opposition on March 8 so will be visible all evening by the end of the month. Mars will rise late evening, it and the other planets are in the morning sky. By the end of the month Mercury will have disappeared while Saturn will rise before midnight.

Mercury rises about 90 minutes before the Sun on March 1st. 45 minutes before sunrise the planet, magnitude -0.3, will be some 8.5° above the horizon in a direction a little to the south of east. Mercury will be 9° below and slightly to the right of Venus.

Mercury will steadily close in on the Sun during the first 3 weeks of March. By the 11th, now at magnitude -0.7, the planet will be only a couple of degrees up 45 minutes before sunrise. It will still be a few degrees below Venus.

On March 24, Mercury will be at superior conjunction. At conjunction the planet will be 202 million km from the Earth and some 53 million km beyond the Sun. At this conjunction it will pass to the south of the Sun, their minimum separation appearing to be just over 1 degree.

After conjunction Mercury will become an evening object setting after the Sun. By the 31st it will set about half an hour later, so is not likely to be visible despite its -1.6 magnitude.

Venus rises nearly 2 hours before the Sun on March 1, reducing to 90 minutes earlier on the 31st. As a result the planet will remain easily visible low in the dawn sky all month. It starts the month in Capricornus but moves into Aquarius on the 11th. On the morning of the 21st, Venus will be half a degree to the right of Neptune. This May give an opportunity to find Neptune using binoculars.

On the morning of March 7 the 7% lit crescent moon will be 8.5° to the upper left of Venus. By the following morning the moon will be only 2.4% lit and 6.8° below Venus. Also Mercury will be 6° to the right of and a little lower than the moon.

Mars rises close to 11 pm on the 1st advancing to 9:45 pm by the 31st so will then be visible to the east late evening. It will also brighten during the month from magnitude 0.3 to -0.5 as the distance between Earth and Mars decreases.

The planet starts March in Libra but moves on into Scorpius on March 13. By the 31st Mars will be 6° from Scorpius and considerably brighter than its rival star.

The moon makes a close approach to Mars on the night of February 29/March 1 At midnight the 64% lit waning moon will 5.5 degrees to the left of Mars. Six hours later the moon, now 62% lit will be 4 below the planet.

A second close approach of the moon to Mars occurs on the night of 28/29 March. For New Zealand viewers the two are closest shortly before dawn when the 78% lit moon will be 4.8 degrees below Mars.

Jupiter is at opposition on March 10, so will then be visible all night. At opposition Jupiter will be 663.5 million km (4.435 AU) from the Earth and nearly another 150 million km further from the Sun.

By the end of the month Jupiter will rise an hour before the Sun making it well placed for viewing by the time the sky darkens. The planet will be in Leo moving to the west. The almost full moon will be a few degrees from Jupiter on the 22nd. Early evening the two will be 3 degrees apart with the moon to the right of Jupiter. Their distance apart will increase during the rest of the night as the moon moves away from the planet.

Saturn begins to move into the evening sky during March. At the start of the month it rises just after midnight, by the end it will rise at 10.20 pm. The planet is in Ophiuchus all month about 9° from Antares and, at the end of March, a similar distance from Mars.

The north pole of Saturn is tilted at an angle of over 26 degrees towards the Earth. The ring system is consequently wide open and readily visible in a small telescope.

The moon passes Saturn twice during the month. On the morning of March 3 the 43% lit moon will be 6 degrees below Saturn at about 4 am, the distance apart increasing to 7 degrees shortly before sunrise. For NZ viewers the two bodies will be closer on the morning of March 30 with the two less than 4 degrees apart at 4 am. Late evening shortly after they rise, the two will 4.5 degrees apart.

Outer planets

Uranus remains in Pisces during March at magnitude 5.9. It sets just after 8.30 pm, 90 minutes after the Sun, on the 1st. So it will be low by the time the sky darkens. By the end of March the planet will set only 20 minutes after the Sun.

Neptune moves up into the dawn sky during March. At first it will rise only 40 minutes before the Sun, increasing to a good 2.5 hours by the end of the month.

The planet is in Aquarius, magnitude 8.0. As Neptune moves up in the sky it will be passed by Venus. On the morning of March 21 the two will be only half a degree apart with Venus to the right of Neptune, the latter slightly lower. There will be no stars brighter than Neptune between the two, although the magnitude 3.7 star lambda Aqr will be 1.5 degrees below it. The window of opportunity to see Neptune in binoculars close to Venus will be fairly short between the time Venus becomes visible and the sky getting too bright to see Neptune.

On the previous morning, the 20th, Venus will be just over a degree above Neptune and on the 22nd it will be a similar distance to the lower right of the faint planet. On the 19th and 23rd the separation will be about 2.5 degrees.

Pluto continues to be in Sagittarius, magnitude 14.4. On the 1st it will be half a degree below the 2.9 magnitude star pi Sgr. At 6 am they will about 37 degrees above the horizon and almost due east. By the end of March the two will be almost a degree apart with Pluto to the lower right of the star

Minor planets

(1) Ceres starts the month only 8 degrees from the Sun. Conjunction is on March 4 after which Ceres will become a morning object.

By the 31st Ceres will rise 90 minutes before the Sun, just before Venus. Ceres at magnitude 9.1 will be almost 7 degrees to the right of the brighter planet.

(4) Vesta, magnitude 8.4, starts March in Pisces, moves into Cetus on the 13th and on into Aries the last day of the month. It is an evening object setting at 10.15 pm on the 1st. By the 31st it will set 90 minutes after the Sun.

The crescent moon will be 5.5 degrees to the right of Vesta on March 12.

Brian Loader  
New Zealand