The Solar System in December 2015

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. The southern summer solstice occurs on December 22 at 5.48 pm NZDT (04:48 UT) SUNRISE, SUNSET and TWILIGHT TIMES in December

                    December  1  NZDT                December 31  NZDT
                    morning  evening                 morning  evening
       SUN: rise:   5.40am,  set:  8.39pm    rise:   5.47am,  set:  8.59pm
  Civil:    starts: 5.10am,  ends: 9.10pm    starts: 5.16am,  ends: 9.31pm
  Nautical: starts: 4.28am,  ends: 9.51pm    starts: 4.33am,  ends:10.14pm 
  Astro:    starts: 3.40am,  ends:10.40pm    starts: 3.42am,  ends:11.05pm

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

  Last quarter:  December  3 at  8.40 pm (07:40 UT)
  New moon:      December 11 at 11.29 pm (10:29 UT)
  First quarter: December 19 at  4.14 am (Dec 18, 15:14 UT) 
  Full moon:     December 26 at 12.12 am (Dec 25, 11:12 UT)

The Planets in December

Only Mercury will be an evening object during December and it will be difficult to see. The remaining naked eye planets will be spread across the morning sky. Saturn too close to the Sun for observation early in the month, all 4 spread widely across the easterly morning sky at the end of December.

Mercury, an evening object, will set some 40 minutes after the Sun on the 1st, only 10 minutes after the end of civil twilight. As a result it will be too low to observed despite a -0.8 magnitude The planet moves rather further from the Sun during December until it reaches its greatest elongation 20° east of the Sun on the 29th. Even then it will set only 75 minutes after the Sun at the end of Nautical twilight. 45 minutes after sunset, Mercury will be only 4.5° above a level horizon towards the west-north-west, so still not an easy object despite its -0.4 magnitude.

Venus, MARS, JUPITER and SATURN in the morning sky during December.

Saturn was at conjunction on the last day of November, so will be too close to the Sun to see during the early part of December.

On the 1st as seen at 5am, the other three planets will be spread out across the evening sky. Most obvious will be Venus, due east and just on 13° up. Mars, magnitude 1.5, will be 14° away to its upper left with an altitude 20°. Jupiter will be 20° beyond Mars and nearly 27° up. Mars and Venus will be in Virgo with the latter 4° below Spica. Jupiter will be in Leo.

During December all three planets will be moving to the east through the stars, Venus most rapidly and Jupiter the slowest. As a result they will spread further apart. Venus will be in Libra by the 12th while Mars will pass Spica on the 24th some 3.5° below the star. Jupiter will remain in Leo but be close to the constellation’s boundary with Virgo by the end of the month. Saturn, in Ophiuchus, will move further into the morning sky to become visible by the end of December.

On the morning of the 31st the 4 planets, from Saturn, through Venus and Mars to Jupiter will be spread across some 77° of sky. Added to that, the Moon, 74% lit, will be 13° beyond Jupiter making a spread of a full 90° in all. At 5am with the Sun just over 8° below the horizon (at Wellington), Venus will be 15.5° up and in a direction 10° south of east. Saturn at magnitude 0.5, will be some 9° up just over 10° to the lower right of Venus. Mars will be on the opposite side of Venus 33° away and 33° above the horizon. Jupiter will be another 35° beyond Mars and 41° above the horizon. Finally the moon will be another 13° beyond Jupiter but at the same altitude.

Earlier in the month, the moon passes the planets. On the morning of December 5 the moon, 37% lit, will be 5.5° from Jupiter, 2 mornings later the moon now 20% lit will be 7° from Mars and the next morning, the 8th, just over 1° from Venus.

Outer Planets

Uranus remains in Pisces during December at magnitude 5.7. It is an evening object. By the end of December it will be setting about 1.30 am.

Neptune is also an evening object throughout December, by the end of December it will set at midnight. The planet is in Aquarius, magnitude 7.9 throughout the month.

Pluto continues to be in Sagittarius throughout December at magnitude 14.4. At the end of the month it sets a few minutes after the Sun.

BRIGHTER ASTEROIDS: (1) Ceres is in Capricornus during December with a magnitude 9.3. It is about 20° from Neptune and like the planet will set close to midnight at the end of December.

(4) Vesta is in Cetus during December although it crosses a corner of Pisces mid month. Its magnitude fades from 7.5 to 8.0 during December. Vesta will be about 15° from Uranus, and will set at a similar time to the planet.

(15) Eunomia starts December in Pegasus but moves into Pisces on the 23rd. Its magnitude fades from 8.9 to 9.4 during December. It is an evening object, by the end of December it will set just after midnight.

(27) Euterpe is in Gemini, it starts December at magnitude 9.4, its brightness peaks at magnitude 8.4 when at opposition on December 25 and drops back to 8.9 by December 31. Euterpe is close to two red stars during the month. On December 14, with a magnitude 8.9, it will be half a degree below mu Gem, mag 2.9. Eight nights later Euterpe, at 8.6, will be 43 arc minutes below eta Gem, mag 3.3. In both instances it will be the brightest object immediately below the star.

Brian Loader  
New Zealand

The solar system in November 2015

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 November

                    November  1  NZDT                November 30  NZDT
                    morning  evening                 morning  evening
       SUN: rise:   6.06am,  set:  8.03pm    rise:   5.40am,  set:  8.38pm
  Civil:    starts: 5.39am,  ends: 8.31pm    starts: 5.10am,  ends: 9.09pm
  Nautical: starts: 5.03am,  ends: 9.07pm    starts: 4.29am,  ends: 9.50pm 
  Astro:    starts: 4.24am,  ends: 9.46pm    starts: 3.41am,  ends:10.38pm

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

  Last quarter:  November  4 at  1.24 am (Nov  3, 12:24 UT)
  New moon:      November 12 at  6.47 am (Nov 11, 17:47 UT)
  First quarter: November 19 at  7.27 pm (06:27 UT) 
  Full moon:     November 26 at 11.44 am (Nov 25, 22:44 UT)

The planets in November

Saturn will be the only naked eye evening planet during October, and that only for the first part of the month. There is more interest in the morning with Venus, Mars and Jupiter forming a loose cluster in the dawn sky. Mercury is not likely to be visible.

Mercury is at superior conjunction on the far side of the Sun on the night November 17/18 NZ time. The planet starts November as a nominal morning object but rises only 18 minutes before the Sun. After conjunction the planet becomes an evening object. By November 30 it will set 40 minutes later than the Sun, but is not likely to be visible in the evening twilight.

At this conjunction, Mercury passes behind the Sun as "seen" from the Earth. The planet moves behind the Sun at about 9.25 pm, an hour after sunset, and doesn't emerge again until about 6.29 am on the 18th, 40 minutes after sunrise the following morning. (Times are as shown by GUIDE 9). So Mercury is behind the Sun for about 9 hours. At conjunction the planet will be 216 million km (1.446 AU) from the Earth and 0.457 AU (68 million km) beyond the Sun.

Venus, MARS and JUPITER in the morning sky during November.

The three planets will start the month as a close group in Leo, although Venus and Mars both move into Virgo within a day. On the 1st Jupiter is about 6° from the other two planets.

Venus and Mars start October close together, within a degree of each other for the first 5 days of the month. On the morning of the 3rd they will be three-quarters of a degree apart with Mars below Venus. The following morning, the two will be very slightly closer, with Mars now to the lower left of Venus.

To see the pairing it will be necessary to look for the planets at least half an hour before sunrise. By then Mars may be lost to naked eye view in the brightening twilight, although Venus should still be easily seen. Binoculars will then readily show Mars, magnitude 1.7. Obviously viewing earlier will make it easier to see Mars, but the two will be low: they rise a little short of two hours before the Sun.

The crescent moon joins the group of planets on the 7th when it will be 2° to the right of Jupiter. By the following morning the moon will have moved past Mars to be 2° to the right of Venus.

For the rest of October, Venus and Mars move across Virgo, with slower moving Mars dropping behind Venus. As a result by the end of October Mars will be higher in the sky than Venus, rising two and a half hours before the Sun while Venus still rises just under two hours before it. Jupiter will be higher still rising over 3 hours before the Sun.

Saturn is heading for its conjunction with the Sun at the end of November. It starts the month setting two hours after the Sun. On the 1st, an hour after sunset, Saturn will be visible 10° up and a good 15° round to the south of due west. Antares will be some 8.5° above the planet, the constellation Scorpius appearing as an upright curled fern with Saturn at its root. During the following nights, Saturn and the constellation will get steadily lower, so that by mid month it will be lost in the evening twilight.

On the 13th the moon, as a very thin crescent, will be just over 4° to the right of Saturn, providing a possible last chance to find Saturn, or maybe an opportunity to find the crescent moon about 36 hours after new. 40 minutes after sunset with the Sun some 8° below the horizon, Saturn and the moon will be less than 4° above the horizon.

At conjunction on the 30th, Saturn will be 11AU, 1644 million km, from the Earth and 10AU beyond the Sun. As "seen" from the Earth, Saturn will pass 1.5° north of the Sun.

Outer planets

Uranus remains in Pisces during November at magnitude 5.7. Opposition was on October 12, so the planet will be visible throughout the evening, setting several hours after midnight.

There is yet another occultation of the Uranus by the moon on November 23. It occurs in the morning after Uranus sets and is visible at night from the south Indian and Southern Oceans to the west of Australia.

Neptune is also an evening object throughout November, setting after midnight but about 90 minutes before Uranus. The planet is at magnitude 7.9 and is in Aquarius throughout the month.

Pluto continues to be in Sagittarius throughout November at magnitude 14.4.

BRIGHTER ASTEROIDS: (1) Ceres starts November in Sagittarius and ends in Capricornus, having crossed a corner of Mica between the 7th and 17th. The asteroid is an evening object setting after midnight, its magnitude dimming slightly from 9.1 to 9.3

(4) Vesta is in Cetus throughout November, its magnitude ranging from 6.9 to 7.5. The asteroid is stationary mid month.

(15) Eunomia remains in Pegasus during November its magnitude varying from 8.4 to 8.9. Also an evening object, it is stationary on the 7th.

(29) Amphitrite is in Pisces all month, its magnitude fading from 8.9 to 9.6. It will be just over 1° north of the mag 3.6 star eta Psc mid month. It sets well after midnight all month.

(192) Nausikaa is in Perseus and rather low in NZ skies. It starts November at magnitude 9.4 a little over a degree from the magnitude 2.9 star zeta Per. During November Nausikaa brightens to magnitude 9.0 at opposition on the 17th. By the end of November it will have faded again to 9.3 The asteroid rises about 11 pm on the 1st and at sunset on the 30th.

Brian Loader  
New Zealand