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.
OUTER PLANETS
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.
MINOR PLANETS
(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