The Solar System In December 2016

Dates and times shown are NZDT (UT + 13 hours).

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

Sunrise, sunset and twilight times in December

                            December  1  NZST               December 31  NZDT
                    morning  evening                 morning  evening
       SUN: rise:   5.39am,  set:  8.40pm    rise:   5.47am,  set:  8.59pm
Twilights
  Civil:    starts: 5.10am,  ends: 9.11pm    starts: 5.17am,  ends: 9.31pm
  Nautical: starts: 4.28am,  ends: 9.52pm    starts: 4.34am,  ends:10.14pm
  Astro:    starts: 3.40am,  ends:10.41pm    starts: 3.43am,  ends:11.05pm

December phases of the moon (times as shown by guide)

          First quarter: December  7 at 10.03 pm (09:03 UT)
  Full moon:     December 14 at  1.06 pm (00:06 UT)
  Last quarter   December 21 at  2.56 pm (01:56 UT)
  New moon:      December 29 at  7.53 pm (06:53 UT)

The SOUTHERN SUMMER SOLSTICE is on 2016 December 21 at 11.45 pm NZDT (10:45 UT)

The planets in December 2016

Venus remains the most obvious planet in the evening sky. Mars, much fainter, is higher in the sky. Mercury May be briefly visible low in the evening sky about an hour after sunset. It will disappear after about mid month. Jupiter is the only planet visible in the morning sky. Saturn is not likely to be seen during December.

Mercury starts December as an evening object with a magnitude -0.5. On the 1st it will set nearly 100 minutes after the Sun. An hour after sunset, shortly before the end of nautical twilight, the planet will be 5° up in a direction 30° to the south of west. Venus will be some 25° away to its upper right.

Throughout the first half of December Mercury will continue to set up to 100 minutes after the Sun. It reaches its greatest elongation, 21° east of the Sun, on the 11th. After mid December the distance of Mercury from the Sun starts decreasing, so it sets earlier. As a result it will be lost in the evening twilight within a few days. The planet is at inferior conjunction between the Earth and Sun on December 29, when it will be 101 million km, 0.675AU, from the Earth and 0.311AU from the Sun.

Venus will remain a brilliant light in the evening sky throughout December reaching magnitude -4.4. It sets shortly before midnight throughout the month. The planet starts December in Sagittarius but, moving to the east, crosses into Capricornus on the 7th. By the 31st Venus will have moved crossed to the eastern edge of the constellation.

The crescent moon will be 6.5° from Venus on the evening of December 3.

Mars starts December in Capricornus at magnitude 0.6. With a distinctly orange colour it will be some 25° to the upper right of Venus. On December 3 Mars passes close to the star iota cap (mag 4.3). They will be closest about 9.30 pm, some 50 minutes after sunset in Wellington, when only 40 arc-seconds apart. about 1% of the moon's diameter. At this distance they will be almost impossible to separate by eye, but fairly easy to do so using binoculars. By midnight Mars will have moved to be just over 4 arc-minutes from the star

Two days later the crescent moon will be 3.5° from Mars.

In mid December Mars moves into Aquarius. It movement across the constellation will be slower than Venus's in Capricornus, as a result the two will be only 12° apart on the 31st. On that evening Mars will have almost caught up Neptune, their separation being some 40 arc-minutes.

Jupiter remains the only one of the naked eye in the December morning sky. On the 1st it rises at 3.15 am, advancing to about 1.30 am by the 31st. The planet is in Virgo, its distance from Spica decreasing from 8 to 4.5° during the month.

On the morning of the 23rd, the moon a day past third quarter, will be just over 3° from Jupiter.

Saturn is at conjunction with the Sun on December 10 so will not be observable during December. At conjunction Saturn will be 1650 million km, 11 au, from the Earth, 10 AU beyond the Sun. By the end of the month it will rise in the morning sky about 75 minutes before the Sun.

Outer Planets

Uranus, at magnitude 5.7, remains in Pisces and is observable all evening. It sets close to 3.30 am on the 1st and two hours earlier on the 31st. The planet is stationary on the 30th. As a result its position changes very little during December, by a distance equivalent to only two-thirds of the diameter of the full moon.

Neptune is in Aquarius at magnitude 7.9 throughout December. It sets about 2 am on the 1st, and midnight at the end of December. The moon is closest to Neptune on the 6th but still 6° at midnight. A few hours later the moon will occult the planet as seen from the northern Atlantic region including northeast Canada and much of Greenland. Mars will close in on Neptune during December.

Pluto at magnitude 14.5 is very low in the early evening sky. It is in Sagittarius setting only 20 minutes after the Sun by the end of December.

Minor Planets

(1) Ceres continues in Cetus during December with its magnitude fading from 8.2 to 8.6. It is stationary mid month resulting in most of its apparent motion being to the north so ending the month some 7° from Uranus.

(18) Melpomene is also in Cetus between 9 and 11 degrees from Ceres. The asteroid, diameter 148 km, fades from magnitude 8.9 to 9.6 during December. Melpomene is on the opposite side of Ceres to Uranus.

Both Ceres and Melpomene are visible all evening not setting until well after midnight.

(4) Vesta is in Cancer throughout December rising about 12.15 am on the 1st and two hours earlier on the 31st. Its magnitude brightens from 7.4 to 6.7 during the month. Vesta starts December 2° from the Beehive cluster, M44. Its westerly retrograde motion sees the asteroid move away from the cluster so that by the 31st they will be 5 degrees apart.

Brian Loader  
New Zealand

The Solar System In November 2016

Dates and times shown are NZDT (UT + 13 hours).

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

Sunrise, sunset and twilight times in November

                            November  1  NZST               November 30  NZDT
                    morning  evening                 morning  evening
       SUN: rise:   6.05am,  set:  8.04pm    rise:   5.40am,  set:  8.39pm
Twilights
  Civil:    starts: 5.38am,  ends: 8.32pm    starts: 5.10am,  ends: 9.10pm
  Nautical: starts: 5.02am,  ends: 9.08pm    starts: 4.29am,  ends: 9.51pm
  Astro:    starts: 4.22am,  ends: 9.48pm    starts: 3.41am,  ends:10.39pm

November phases of the moon (times as shown by guide)

          First quarter: November  8 at  8.51 am (Nov  7, 19:51 UT)
  Full moon:     November 15 at  2.52 am (Nov 14, 13:52 UT)
  Last quarter   November 21 at  9.33 pm ( 8:33 UT)
  New moon:      November 30 at  1.18 am (Nov 29, 12:18 UT)

The planets in November 2016

Mercury will be visible, low, early evening near the end of November while brilliant Venus will be easily visible until late evening all month. Mars will be even better placed. Saturn starts the month close to Venus but slips lower in the sky during November to disappear into the evening twilight by the end of the month. Meanwhile Jupiter moves up into the morning sky.

Mercury is an evening object during November. Having been at superior conjunction with the Sun on the 28th, the planet will set less than 15 minutes after the Sun at the beginning of the month, making it unobservable. By the month’s end the time difference will have increased to an hour and three-quarters. Thus towards the end of November the planet, at magnitude -0.5, should be visible once the sky is sufficiently dark. Look for it very low to the southwest in the direction of the set Sun.

Venus, by contrast to Mercury, will be visible all evening, not setting until almost midnight by the end of the month. During November Venus moves across Ophiuchus, passing close to theta Oph, magnitude 3.2, on the 5th. The planet moves into Sagittarius on the 9th. On the 17th it will be within 20 arc-minutes of lambda Sgr, mag 2.8 and on the 23rd less than a degree from Nunki, sigma Sgr. At magnitude 2.1, Nunki is the brightest star in the handle of the “teapot”.

At the beginning of November, Venus will be a few degrees above Saturn. The crescent moon joins the pair on the 3rd. The moon will be at about the same altitude as Saturn, with Venus some 5 degrees above them.

Mars will be higher than Venus in the evening sky setting just before 2 am on the 1st and just after 1 am on the 30th. The planet starts November in Sagittarius, close to the position Venus will occupy at the end of the month. During November, Mars will move into Capricornus on the 8th and be well across the constellation by the 30th.

Mars dims slightly during November, from magnitude 0.4 to 0.6 as the Earth moves further from the plant. On the 6th, the moon, as a thick crescent, will be 6 degrees below Mars.

Saturn will remain in Ophiuchus all month. At the beginning of November it will set nearly 3 hours after the Sun, so remaining easily visible with an altitude of 18 degrees at the end of nautical twilight. By the end of November, Saturn will set 37 minutes after the Sun, only 6 minutes after the end of civil twilight, so making it very difficult to see.

Jupiter is the only one of the naked eye planets in the November morning sky. It rises an hour before the Sun on the 1st, 2 hours and 20 minutes before it on the 30th. The planet is in Virgo all month, by the end of November it will be 8 degrees from Spica, at mag 1.1 the brightest star in the constellation.

On the morning of the 25th the crescent moon will be 5.5 deg to the left of Jupiter. The following morning th moon, showing a rather thinner crescent, will be 6.5 degrees from Spica.

Outer Planets

Uranus, at magnitude 5.7, remains in Pisces and is observable all evening. By the 30th Uranus will set 2 hours before sunrise. On the evening of the 12 the near full moon will be 2 degrees above the planet.

Neptune is in Aquarius at magnitude 7.9 throughout November. It sets about 4 am on the 1st, and 2 am by the end of November. On the night of November 9/10 the planet will be occulted by the moon an event visible from most of Scandinavia and a large part of Russia. From NZ the moon will be 2 degrees below Neptune as seen in the early morning sky of the 10th.

Pluto at magnitude 14.4 to 14.5 continues in Sagittarius as an early evening object, setting about 1 am on the 1st and 11.15 pm on the 30th. On November 5 the crescent moon will be 3.5 degrees from Pluto, with the planet itself half the moon’s diameter from the 3.7 magnitude star omega Sgr.

Minor Planets

(1) Ceres is in Cetus during November with its magnitude fading from 7.6 to 8.1. Ceres is about 11 degrees from Uranus and, on the 12th, 10 degrees from the moon.

(18) Melpomene is also in Cetus between 7 and 8 degrees from Ceres. The asteroid, diameter 148 km, fades from magnitude 8.1 to 8.8 during November. Melpomene is on the opposite side of Ceres to Uranus.

Both Ceres and Melpomene are visible all evening not setting until well after midnight.

(4) Vesta is in Cancer throughout November rising about 2am on the 1st and shortly after midnight on the 30th. Its magnitude brightens from 7.9 to 7.4 during the month. Vesta’s path in Cancer will take it towards M44, the Beehive cluster. On the 30th it will be 2 degrees from M44 but it is then stationary. Subsequently it will move away again from the cluster during December.

Brian Loader  
New Zealand