Solar System notes for May, 2017
The Solar System In May 2017
Dates and times shown are NZST (UT + 12 hours) unless otherwise stated.
Sunrise, sunset and twilight times in May
Times are for Wellington. They will vary by a few minutes elsewhere in NZ.
May 1 NZST May 30 NZST SUN: rise: 7.05am, set: 5.30pm rise: 7.33am, set: 5.03pm Twilights morning evening morning evening Civil: starts: 6.39am, ends: 5.56pm starts: 7.05am, ends: 5.31pm Nautical: starts: 6.06am, ends: 6.29pm starts: 6.31am, ends: 6.08pm Astro: starts: 5.34am, ends: 7.01pm starts: 5.58am, ends: 6.39pm
May phases of the moon (times nzst, as shown by guide)
First quarter: May 3 at 2.47 pm (2:47 UT) Full moon: May 11 at 9.43 am (May 10, 21:43 UT) Last quarter May 19 at 12.33 pm (00:33 UT) New moon: May 26 at 7.45 am (May 25, 19:45 UT)
Occultation Of Regulus
A lunar occultation of Regulus on May 4 is visible from New Zealand and Australia. The disappearance is at the ?dark? limb of the moon so readily observable in binoculars. It will be just before sunset at Perth in Western Australia but should be observable there. Elsewhere, further east, the occultation will be after the Sun has set.
The reappearance from occultation will be at the sunlit limb of the moon, making it a little more difficult to observe and time accurately.
Disappearance times in New Zealand range from 10.40 pm in the southwest to 10.53 pm at East Cape. The corresponding range of reappearance times is 11.47 pm to 11.58 pm. Observers should generate their local predictions using Dave herald?s Occult program to obtain precise time predictions for their own locality.
The planets in May 2017
Jupiter will be prominent in the evening sky with Saturn appearing later to the east. Mars is getting too close to the Sun for easy observation. Mercury will be at its morning sky best for the year in the 2nd part of the month, well placed an hour before sunrise. It will very much outshone by Venus some way above it.
Mercury, in the morning sky, rises 90 minutes before the Sun on May 1 and nearly 2 hours earlier than the Sun at the end of the month. With a low altitude and a magnitude 2.4 the planet will not be readily observable at the beginning of May.
Things rapidly improve during the first half of May as Mercury brightens and moves further from the Sun. The planet reaches its greatest elongation, 26° west of the Sun mid month. On the morning of May 18 at 6.20 am, hour before sunrise at Wellington, Mercury will be nearly 13° above the horizon with a magnitude 0.4. Venus will be some 19° above and a little to the left of the fainter planet. The middle of May will give the best opportunity to observe Mercury in the morning sky this year. By the end of May the planet will be brighter at magnitude -0.3 but getting little lower.
Mercury stars May in Pisces, it crosses a corner of Cetus between May 19 and 22 before entering Aries. On the morning of May 24 a thin crescent moon will be 3.5° above Mercury
Venus is an easy to find morning object in May. It rises over 3 hours before the Sun on the 1st increasing to almost 4 hours earlier by the 31st. Venus is following Mercury across Pisces and ends May quite close to the position in the stars that Mercury was in at the beginning of the month.
On the morning of the 23rd the crescent moon will be about 3.5° to the lower right of Venus. On 31st, Venus will also be 3.5° above Uranus, so the two will be visible in a 5° binocular field.
Mars slowly gets lower in the early evening sky. At magnitude 1.6 to 1.7 and a low altitude it will be a difficult object in the twilight. It sets 75 minutes after the Sun on the 1st, an hour after the Sun on the 31st.
On the evening of the 27th a very thin crescent moon will be about 4.5° above Mars. But at 5.45 pm when the Sun is only 8° below the horizon, Mars? altitude at Wellington will be slightly less than 4°
Jupiter will be a prominent object throughout the evening sky following its opposition at the beginning of April. Early evening in May will find the planet just under 10° to the left of the first magnitude star Spica, alpha Virginis. Some 8 hours later the anticlockwise rotation of the sky will bring Spica to a position directly above Jupiter.
The nearly full moon will be 5° to the lower right of Jupiter on May 8.
Saturn will rise at 8 pm on the 1st of May and a good 2 hours earlier by the 31st. It brightens slightly during the month from 0.3 to 0.1 making it the brightest object to the east. There are a number of the brighter, 2nd magnitude stars in Sagittarius some 10 to 20° to its Saturn?s left.
The planet itself starts the month in Sagittarius. It moves only slowly to the west through the stars, less than 2° during the month. Even so this is sufficient to take it into Ophiuchus mid month.
Currently Saturn is 22° south of the equator. As a result when due north it will be very high in NZ skies. This will be about 3.30 am early May, advancing to 1.30 late May.
The moon, a little past full, will be some 7° from Saturn on the evenings of May 13 and 14. The position of the moon with reference to Saturn on the two night will be very different. Moon and planet are closest about 10 am on the morning while they are below the horizon for NZ.
Uranus begins to move up into the morning sky shortly before sunrise, following its conjunction with the Sun mid April. At the beginning of May Uranus will be close to Mercury but too low for easy observation. At the end of May a much brighter marker, Venus, will be 3° above the outer planet. By then Uranus will rise just before 4 am, with Venus rising 15 minutes earlier. So at 6.30 am, an hour before sunrise, the two will be at a comfortable 25° altitude.
Neptune rises early into the morning sky, soon after 2am on May 1 and 2 hours earlier on May 31. The planet remains in Aquarius at magnitude 7.9, moving only half a degree during the month. On the 1st it will be 18.5° above and a little left of Venus.
Pluto, magnitude 14.4, is moving into the evening sky rising at 9.40 pm on the 1st, 2 hours earlier on the 31st. It will remain in Sagittarius about 2.5° from the 2.9 magnitude star pi Sgr.
(1) Ceres, in Taurus is too close to the Sun to observe in May. It is at conjunction early June.
(4) Vesta is in Cancer during May with a magnitude changing from 8.0 to 8.2. On the 1st it sets about 10.20pm. By the 31st it will be setting about an hour earlier. The moon will be just over 6° above Vesta in May 2. It will be in a similar position again, compared to Vesta, on the 30th but about half a degree closer.
Brian Loader New Zealand
Solar System notes for April, 2017
The Solar System In April 2017
NZ reverts to NZST (UT +12 hours) on April 2 at 3am. Consequently dates and times shown are NZST apart for any on April 1.
Sunrise, sunset and twilight times in April
Times are for Wellington. They will vary by a few minutes elsewhere in NZ. April 1 NZDT April 30 NZST morning evening morning evening SUN: rise: 7.33am, set: 7.15pm rise: 7.04am, set: 5.31pm Twilights Civil: starts: 7.09am, ends: 7.40pm starts: 6.38am, ends: 5.58pm Nautical: starts: 6.37am, ends: 8.12pm starts: 6.05am, ends: 6.30pm Astro: starts: 6.04am, ends: 8.44pm starts: 5.33am, ends: 7.02pm
April phases of the moon (times nzst, as shown by guide)
First quarter: April 4 at 6.40 am (Apr 3, 6:40 UT) Full moon: April 11 at 6.08 pm (06:08 UT) Last quarter April 19 at 4.07 pm (04:07 UT) New moon: April 27 at 12.16 am (Apr 26, 12:16 UT)
The planets in April 2017
Jupiter becomes visible all night so is a brilliant object in the evening sky. Saturn will be to the east by late evening. Mars will be low to the west after sunset setting before the end of astronomical twilight. Venus moves up in the morning sky during April, a brilliant object to the east. Mercury is too close to the Sun to observe all month.
Mercury is virtually unobservable throughout April. It is at inferior conjunction between Earth and Sun at 5pm on the 20th. At conjunction the planet will pass 1.5° north of the Sun as "seen" from the Earth. Mercury will be 86 million km from the Earth and 64.4 million km from the Sun.
On the 1st Mercury, in the evening sky, will set only 30 minutes after the Sun. On the 30th, in the morning sky, it rises about 80 minutes before the Sun but at magnitude 2.6 is not likely to be visible due to twilight.
Venus is a morning object in April. On the 1st it will rise some 45 minutes before the Sun, by the 30th it will rise more than 3 hours earlier than the Sun.
The planet will not be readily visible on April 1 when it is only 12° from the Sun. Its distance from the Sun increases steadily throughout April, particularly early in the month as Venus moves to the west through the stars, away from the easterly moving Sun. This will make it an easy object within a few days. It will be visible a little to the north of east at first shortly before sunrise.
Venus is in Pisces all month and is stationary on April 13 after which it will start moving to the east but less rapidly than the Sun. The position of the planet relative to the stars will change little during the month
The morning of the 24th will find the crescent moon some 4.5° to the upper right of Venus
Mars will remain a low early evening object during April. On the 1st it sets just over 80 minutes after the Sun, dropping only slightly to 75 minutes later on the 30th. It will be low, with a magnitude 1.5, visible only briefly as the sky darkens following sunset. Mars will set a little before the end of Astronomical twilight so not be an easy object.
During April, the planet moves to the east through Aries and on into Taurus on the 12th. On the 21st and 22nd it will be 3.5° above the Pleiades, by the end of April Mars will be 7° below the similarly coloured star Aldebaran. On the 28th the moon, a very thin crescent less than 5% lit, will be 5° to the upper left of Mars.
Jupiter is at opposition on April 8, NZ time. At opposition Jupiter will be 4.5 AU, 666 million km from the Earth and a further 150 million km from the Sun. The planet will be in Virgo moving in a retrograde sense to the west as the Earth overtakes it. Jupiter starts the month just over 6° from Spica, its slow westerly motion taking it to nearly 9.5° from the star on the 30th.
The full moon will be 6.5° from Jupiter on the evening of April 11, the moon at the apex of an inverted triangle formed by it, Jupiter and Spica.
Saturn will rise close to 11 pm NZDT 1st of April, which becomes 10pm NZST on the 3rd with the time of rise advancing to just after 8 pm by the 30th. Thus it becomes a prominent later evening object to the east at magnitude 0.3 to the east during the month. It will, of course, be readily visible in the morning sky. By the end of April Saturn will be highest and due north about 3.40 am.
Saturn is stationary on the 6th, after which it will start moving to the west, but its position in Sagittarius will change little throughout the month.
The 75% lit waning moon will be 3.5° to the lower right of Saturn on the morning of April 17, with the two closest at about 6 am.
Uranus is at conjunction with the Sun on April 14. Hence it will be too close to the Sun to observe throughout April.
Neptune, in the morning sky, rises about two and a half hours before the Sun on the 1st and nearly 5 hours earlier on the 30th. The planet is in Aquarius at magnitude 8.
Pluto, magnitude 14.4, is in the morning sky rising about 12.40 am, NZDT, on the 1st and 9.45 pm on the 30th. It will remain in Sagittarius just under 2.5° from the 2.9 magnitude star pi Sgr.
(1) Ceres is an early evening object, brightening slightly from magnitude 9.1 to 8.9 during the month. It is quite close to Mars moving on a path almost parallel to the major planet which overtakes Ceres during the month. On the 1st they are 4° apart with Ceres above Mars. On the 8th they are at their closest, 3° apart. By the 30th Ceres is will be dropping behind Mars, the two then being 5° apart.
On the 12th both Ceres and Mars move from Aries to Taurus, with Ceres crossing the border shortly before Mars.
(4) Vesta, an evening object in April, is in Gemini. It passes Pollux, magnitude 1.2, early in April, the two being closest on April 7, just over 2° apart. The asteroid moves on into Cancer on the 24th. Vesta dims slightly during the month from magnitude 7.7 to 8.0. It sets about 12.45 am, NZDT, on the 1st and just before 10.30 pm, NZST, on the 30th.
Brian Loader New Zealand