The Solar System In December 2017

Dates and times shown are NZDT (UT + 13 hours) unless otherwise stated. Times are for Wellington. They will vary by a few minutes elsewhere in NZ.

The southern summer solstice is on December 22 with the Sun appearing furthest south at 5.28 am, about 12 minutes before sunrise at Wellington.

 

             December  1  NZDT          December 31  NZDT
      SUN:  rise 5.40am, set 8.39pm    rise 5.47am, set 8.59pm
Twilights    morning     evening        morning     evening

Civil:    start 5.10am, end 9.10pm   start 5.17am, end 9.31pm

Nautical: start 4.28am, end 9.52pm   start 4.34am, end10.14pm

Astro:    start 3.40am, end10.41pm   start 3.42am, end11.05pm

 

December Phases of the Moon (times NZDT, as shown by GUIDE)

  Full moon:     December  4 at  4.47am (Dec  3, 15:47 UT)
  Last quarter   December 10 at  8.51pm (07:51 UT)
  New moon:      December 18 at  7.30pm (16:30 UT)
  First quarter: December 26 at 10.20pm (09:20 UT)

The Planets in December 2018

Of the five naked eye planets only Mars and Jupiter will be far enough from the Sun for viewing and they are in the morning sky. Mars will be the better placed, especially early in the month.

Mercury, Venus and Saturn are all close to the Sun and at best make difficult objects. Mercury and Saturn are in the early evening sky at the beginning of December but reach conjunction during the month.

Mars starts December in Virgo rising more than two hours before the Sun. On the 1st it will be 3° below Spica, the planet being the fainter object at magnitude 1.7 compared to Spica's 1.1. On the 21st Mars will cross into Libra. By the 31st it will rise 3 hours before the Sun

During December Mars will be catching up with Jupiter, they are 16° apart on the 1st but only 3° apart on the 31st.

Jupiter is in Libra all month. It rises just over 80 minutes before the Sun on the 1st. This is close to the start of nautical twilight so Jupiter will not be an easy object low in the twilit sky. By the end of December Jupiter rises more than 3 hours before the Sun, only 9 minutes after Mars. The two planets will be more than 20° up an hour before sunrise, Jupiter more than 3 magnitudes brighter than Mars.

The crescent moon will be some 5° below Mars on the morning of the 14th and a similar distance from Jupiter the following morning, also Vesta will be less than a degree to the right of the moon.

Mercury starts the month as an evening object setting nearly 2 hours after the Sun. 45 minutes after sunset, Mercury at magnitude 0.0 will be 8° above the horizon towards the west-south-west. On the 3rd of December, the planet is stationary, after which it starts moving to the west towards the Sun which itself will be moving to the east. Their separation will decrease rapidly over the next few days until Mercury is at inferior conjunction with the Sun on the 13th. At conjunction Mercury will pass 1.5° north of the Sun.

After conjunction Mercury will be a morning object. By the end of the month it will rise 85 minutes before the Sun, so will be a very low object a little to the south of east as the sky brightens.

Saturn will also finally disappear from the evening sky during December. On the 1st it will be nearly 3° to the lower right of Mercury, making Saturn even more difficult to see. It is at conjunction with the Sun on the 22nd. After conjunction it too becomes a morning object but will be too low for easy observation rising only half an hour before the Sun on the 31st.

Venus is close to the Sun all month. It rises 28 minutes before the Sun on the 1st. This reduces to only 11 minutes earlier on the 31st.

Outer Planets

Uranus is in Pisces during December. It is well placed in the evening sky once it is dark. It sets about 1.45 am at the end of December.

Neptune is also an evening object setting about 100 minutes before Uranus. So at the end of December it sets just after midnight. The planet is an Aquarius at magnitude 7.9.

Pluto, magnitude 14.5, remains in Sagittarius. By the end of December it sets only have an hour after the Sun.

Brightest Minor Planets

(1) Ceres is a morning object in Leo, brightening from magnitude 8.1 to 7.5 during the month.

(2) Pallas is in Fornax during December. It dims a little from magnitude 8.4 to 8.7 during the month.

(4) Vesta is in Libra during December quite close to Jupiter. At their closest on December 11, Vesta will be about 4° from the gas giant. Vesta at magnitude 8 will rise two and a half hours before the Sun on the 31st.

(7) Iris dims from magnitude 7.8 to 8.6 during December. The asteroid is an evening object in Aries.

(8) Flora is a morning object brightening from magnitude 9.1 to 8.3 during December. It is in Gemini two days short of opposition on the 31st.

(20) Massalia starts December in Orion at magnitude 9.0. It crosses into Taurus on the 11th, reaches opposition on the 17th with a magnitude 8.4 and fades to 8.9 by the end of the month. It is in the sky most of the night.

Brian Loader  
New Zealand

The Solar System In November 2017

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

Sunrise, Sunset and Twilight Times in November

Times are for Wellington. They will vary by a few minutes elsewhere in NZ.

                    November  1  NZDT               November 31  NZST
       SUN: rise:   6.05am,  set:  8.04pm    rise:   5.40am,  set:  8.38pm
  Twilights     morning       evening            morning       evening
  Civil:    starts: 5.38am,  ends: 8.32pm    starts: 5.10am,  ends: 9.09pm
  Nautical: starts: 5.02am,  ends: 9.08pm    starts: 4.29am,  ends: 9.51pm
  Astro:    starts: 4.23am,  ends: 9.47pm    starts: 3.41am,  ends:10.39pm

November Phases of the Moon (times NZST, as shown by GUIDE)

          Full moon:     November  4 at  6.23 pm (05:23 UT)
  Last quarter   November 11 at  9.37 am (Nov 10, 20:37 UT)
  New moon:      November 19 at 12.42 am (Nov 18, 11:42 UT)
  First quarter: November 27 at  6.03 am (Nov 26, 17:03 UT)

The Planets in November 2017

Two planets are visible in the evening sky, Mercury and Saturn. Mercury sets over two hours before Saturn on the 1st, but some 15 minutes later than Saturn on the 30th.

The other three naked eye planets are morning objects. Venus rises about 30 minutes before the Sun all month, Mars increases its distance from the Sun so rising 2 hours before the Sun at the end of November. Jupiter will be too close to the Sun to see at the beginning of the month, but should become briefly visible very low about 50 minutes before sunrise by the end of the month

Evening Sky

Mercury is an early evening object but will be very low when the sky is dark enough to see the planet. On the 1st , 45 minutes after sunset, the planet at magnitude -0.4 will be 5°above the horizon. At the end of November, 45 minutes after sunset, Mercury will be a little higher, 8.5° and slightly fainter, magnitude -0.1.

On the last few days of November Mercury will be quite close to Saturn, the latter being some 3° to the lower right of Mercury. Earlier in the month on the evening of the 13th the planet will be just over 2°to the right of Antares. Earlier still in November the planet will be less than 2 arc minutes from the magnitude star delta Scorpii on the morning of November 8, in daylight for NZ.

Saturn is an early evening object during November. It sets just over 3 and a half hours after the Sun on the first, an interval decreasing to 86 minutes by the 30th. The planet stars November in Ophiuchus but moves on into Sagittarius mid month.

The crescent moon will be some 4.5° to the right of Saturn as seen soon after sunset on the 21st.

Morning Sky

Venus is a nominal morning object, but it rises only about half an hour before the Sun all month. This will make it a difficult object despite its brightness, magnitude -3.9. Look for the planet low to the east shortly before sunrise. During the month Venus passes Jupiter, the two are less than half a degree apart on the morning of November 14. Shortly before sunrise the two will be less than 4° up and a little to the south of east.

Mars rises 75 minutes before the Sun on the 1st and 2 hours before it on the 30th, so is better placed in the morning sky than is Venus. But it is 5 magnitudes fainter. Mars is in Virgo and at the end of the month will be only 3° from Spica, at magnitude 1.1 the brightest star in the constellation. The crescent moon will be some 5° to the left of Mars on the morning of the 15th.

Jupiter is the third of the morning planets. It was at conjunction with the Sun at the end of October, so will be too close to the Sun to see during the first part of November. By the end of the month it will rise 80 minutes before the Sun. 40 minutes before sunrise on the morning of the 30th, Jupiter will be about 6.5° up and a little to the south of east. The planet starts the month in Virgo but crosses into Libra mid month.

Outer Planets

Uranus is in Pisces during November. Having been at opposition during October, it will be well paced in the evening sky once it is dark. The planet rises 80 minutes before sunset on the 1st increasing to almost 4 hours earlier on the 30th. The almost full moon is a few degrees from Uranus on the 3rd.

Neptune rises some three and three-quarter hours before Uranus, so is also a well placed evening object. By the end of November it sets about 2am. The planet is in Aquarius at magnitude 7.9. The moon close to first quarter is about 1.5° from Neptune on the 27th.

Pluto, magnitude 14.4, remains in Sagittarius. Like Uranus and Neptune, it is an evening object, although it will set near 11.30 pm by the end of the month. During November, Pluto will be slowly moving away from the 2.9 magnitude star pi Sgr. By the 30th they will be a little over 1.5° apart.

Minor Planets

(1) Ceres is a morning object in Cancer. It starts November in Cancer at magnitude 8.5, crosses into Leo on the 21st and ends the month at magnitude 8.1

(2) Pallas is in Fornax during November. It is at its brightest, magnitude 8.2 in the first part of the month, being at opposition on the 8th. When it will by some 254 million km, 1.70 AU, from the Earth. After opposition it will slowly start to fade but still be magnitude 8.4 at the end of November.

(4) Vesta is in Virgo during most of November. It will be a low morning 8th magnitude object. On the 1st it will be 3.5° from Venus but the latter will soon move away from the asteroid. Vesta crosses into Libra on the 29th, by then it will be less than 6° from Jupiter.

(7) Iris, following its opposition at the end of October, will dim a little from magnitude 6.9 to 7.7, the reverse of October. Even so, it remains the brightest asteroid this month. Iris's path in Aries takes it away from Hamal and towards beta Ari, magnitude 2.6. At their closest the two are just over a degree apart on the 8th, with Iris to the right of beta as seen about 10 pm. The asteroid's apparent movement is mostly to the south and it is stationary at the end of the month.

(8) Flora brightens from magnitude 9.7 to 9.1 during November It is a morning object rising about 1 am and spends the month in Gemini. It starts November about 1.5° from eta Gem magnitude 3.6. The two are closest on the morning of the 8th with Flora 0.25° north of eta.

(20) Massalia, like Flora brightens from magnitude 9.8 to 9.0 during November. It also starts the month in Gemini, but further west than Iris, near the border with Orion which Massalia crosses into on the 27th. Massalia starts November about 1.8° to the west of the red star Praepes, eta gem

Brian Loader  
New Zealand