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All times are adjusted for daylight saving Brilliant Venus in the south-west and Jupiter in the south-east dominate our evening sky. In the later part of January they will be joined by Mars and Saturn. The most notable celestial event will be the total lunar eclipse in the early hours of December 11. We then have the summer solstice on December 22 and in January New Zealand’s biggest astronomical convention, Stardate.
Planet positions  
The charts show the heliocentric orbital positions of the planets for the first day of December and the first day of January. The planets are orbiting in an anti-clockwise direction and smaller images show the positions of the terrestrial planets for the 15th of each month. The orbits of the terrestrial planets are to scale, planets beyond Mars are placed in shells. A line drawn from the Earth through the Sun will reveal the constellation of the Zodiac that the Sun is moving through.
| MERCURY - MERCURY is a morning star from the second week in December and throughout
January. The planet will be difficult to spot because at best it rises a little more
than 80 minutes before the Sun. At Stardate Mercury will rise an hour before the Sun.
Its magnitude will be -0.6. In a telescope, it will look like a tiny gibbous, almost full
moon (phase 96%), 4.8” in diameter.
Mercury is at inferior conjunction (between the Earth and the Sun) on December 4.
It reaches perihelion, its closest orbital point to the Sun, on December 5. Greatest
elongation occurs on December 23 when Mercury will be 22° west of the Sun. | 
| VENUS -
VENUS is the brilliant evening star visible in the south-western sky after sunset. T
hroughout December and January it sets about 2 hours after the Sun. On January
13 Venus will be 1.2° south of Neptune. At Stardate its magnitude will be -4.0 and
in a telescope, it will look like a small gibbous moon (phase 77%), 14.3” in diameter. | 
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MARS -
MARS is a morning star in December but by the second week of January it will be rising
before midnight. Mars is slowly moving eastward and moves from Leo into Virgo in
mid-January. At Stardate it will be seen as a bright reddish star of magnitude -0.3. In a
telescope it will show a slightly gibbous phase (94%) 10.9” in diameter. Mars is
stationary on January 25. | 
| JUPITER -
JUPITER is a bright star-like object in Aries and is visible throughout the evening.
At Stardate its magnitude will be -2.4 and its telescopic diameter 40.5”. At 10:30 pm
the Jovian Satellites will have the following configuration from west to east:
Friday Jan 20 Callisto – Ganymede – Jupiter – Europa – Io
Saturday Jan 21 Callisto – Ganymede – Io – Jupiter – Europa
Sunday Jan 22 Europa – Jupiter – Callisto – Ganymede – Io
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SATURN - SATURN is a morning star in Virgo, close to Spica. At Stardate its magnitude will be
+0.6 and the telescopic diameter of its orb 17.3”. | 
| URANUS - URANUS is an evening star in Pisces. At Stardate its magnitude will be +5.9, making
it just visible with the unaided eye from a clear dark sky. Its telescopic diameter will be
3.4” and its co-ordinates on January 21 will be 0h 06m, -0° 06’. | 
| NEPTUNE -NEPTUNE also sets after midnight in November, about 75 minutes before
Uranus. Thus Neptune will also be well placed in the evening sky for
viewing, although it will be low by midnight at the end of the month.
Neptune, magnitude 7.9, is in Aquarius near its border with Capricornus. | 
| PLUTO - PLUTO reaches solar conjunction on December 29. Consequently it will be setting in
the evening twilight before this date, and rising in the dawn twilight after. Pluto is in Sagittarius and, with a magnitude of +14, it is visible only in large telescopes. At
Stardate Pluto will rise 90 minutes before the Sun. On January 21 its co-ordinates
will be 18h 33m 14s, -19° 19’, 06”. |
The Solar System at Stardate
If you would like to view the Sun, Moon and planets through a variety of telescopes, join us at Stardate in the Hawkes Bay from the evening of Friday January 20 through to the evening of Sunday the 22nd. On the evening of Saturday the 21st through to the morning of the 22nd, the rise and set times of planetary objects are as follows: 8:52 pm Sun sets (Image: Planets montage) 
10:10 pm Neptune sets
10:32 pm Venus sets
11:20 pm Mars rises
11:25 pm Uranus sets
12:30 am Saturn rises
1:40 am Jupiter sets
4:40 pm Pluto rises
4:44 am Moon rises
5:12 am Mercury rises
6:13 am Sun rises
=============================================================1. Total Eclipse of the
Moon - December 10/11
---------------------------------------------
The mid time of this eclipse will be just before 3:32 am NZDT on the
morning of December 11. The timing means the eclipse will be visible
almost in its entirety from New Zealand and fully from Australia.
The predicted times for the various stages are:
UT Dec 10 NZDT Dec 11
First contact with penumbra 11:33:23 12:33:23 am
First contact with umbra 12:45:34 1:45:34 am
Total eclipse starts 14:06:26 3:06:26 am
Mid eclipse 14:31:50 3:31:50 am
Total eclipse ends 14:57:16 3:57:16 am
Last contact with umbra 16:18:09 5:18:09 am
Last contact with penumbra 17:30:13 Moon set in NZ
The moon is at its furthest north for the month at the time of the eclipse
so it will be at its lowest for New Zealand. Its altitude at mid eclipse
will range from 21° at Auckland to 15° at Invercargill. The moon will set
throughout NZ close to 6am, before it entirely leaves the penumbra. By
this time there will be no noticeable effect of the eclipse. Sunrise is
about 5.45 am, so there will be considerable twilight by the time the moon
leaves the umbra.
The entire eclipse will be visible from Australia and from east Asia with
the moon higher in the sky than in NZ.
-- Brian Loader
==============================================================2. The Solar System in
December
-------------------------------
The usual notes on the visibility of the Planets for December 2011 are on
the RASNZ web site: http://www.rasnz.org.nz/SolarSys/Dec_11.htm. Notes
for January 2012 will be on line in a few days.
Total eclipse of the moon, December 10/11. See Item 1 for details.
The southern summer solstice is on December 22 with the Sun furthest south
at about 6.31 pm. The earliest sunrise for the year will be on the
morning of the eclipse of the moon.
THE PLANETS IN DECEMBER
Venus and Jupiter are obvious objects in the evening sky, Venus fairly low
to the south of west after sunset, Jupiter a little higher to the north.
Mars and Saturn remain morning objects, Saturn rises increasingly earlier
before the Sun so becoming more readily visible an hour before sunrise.
Mercury is too close to the Sun most of the month, but may be briefly
visible as a very low object in the dawn sky at the end of December.
EVENING SKY - VENUS and JUPITER
VENUS will set a little over 2 hours after the Sun throughout December, so
will be easily seen about 15° up half an hour after sunset. It will be
moving through Sagittarius up to December 20 and will pass several of the
brighter stars of the constellation, including the handle of the teapot,
during the first 10 days.
After the 20th, the planet will be in Capricornus where the 8% lit
crescent moon joins it on the 27th.
JUPITER will be readily visible to the north as the sky darkens following
sunset during December. It transits about 10.40 pm NZDT on the 1st,
advancing to 8.40 pm on the 31st, so shortly before sunset.
The planet starts the month in Aries moving in a retrograde sense to the
west. It crosses into Pisces on the 5th, but stays close to the border of
the two constellations for the rest of the month. It is stationary on the
26th after which it will start moving to the east.
On the evening of December 6 the 85% lit moon will be just under 7° to the
lower left of Jupiter, the two getting slightly closer before they set
early the following morning. The following evening the moon now 91% lit
will be 10° to the lower right of Jupiter.
MORNING SKY
MERCURY is at inferior conjunction on December 4 and will become a morning
object rising before the Sun. It will be the end of December before the
planet rises early enough for a possible sighting in the dawn sky. Even
then it will be a difficult object. On the morning of the 31st it will
rise about 80 minutes before the Sun. An hour before sunrise it will be
only 3° above the horizon roughly half way between east and southeast.
Mercury will be at magnitude -0.4.
MARS remains in the morning sky during December. It will rise about 2am
early in the month and just over an hour earlier by the end. Mars will be
moving to the east through Leo, taking it away from Regulus. The two will
be about 10° apart at the beginning of the month and 20° apart at the end.
An hour before sunrise, Regulus will be to the left of Mars.
The moon, just before last quarter, will be about 8.5° above Mars on the
morning of December 18.
SATURN moves further up into the morning sky during December. By the end
of the month it will rise about three and a half hours before the Sun,
making it easily visible to any early risers an hour before sunrise. The
planet remains in Virgo and will be about 5° below Spica. Saturn will be
slightly brighter than the star.
The crescent moon will be some 8° to the right of Saturn on the morning of
the 21st. The previous morning it will be 10° away the other side of
Saturn and to the upper left of Spica.
***********
URANUS will set a little before 3am in New Zealand at the beginning of
December and about an hour after midnight by the end of the month. So it
will remain quite well placed for viewing in the evening after the sky is
dark. The planet is in Pisces with a magnitude 5.8.
NEPTUNE sets about 1.30am at the beginning of December and a little before
midnight at the end of the month. Early in December, about an hour after
sunset Neptune will be to the west 25° above the horizon. At the same time
at the end of December it will be only some 6° up, so becoming difficult
to observe. The planet at magnitude 7.9, is in Aquarius near its border
with Capricornus.
BRIGHTER ASTEROIDS:
(1) Ceres, like Neptune, is in Aquarius and so also in the evening sky.
It sets about 3am early in December, a little after 1 am at the end.
Ceres fades a little during the month from 8.8 to 9.1.
(4) Vesta is in Capricornus at the beginning of December but joins Ceres
in Aquarius on December 9. The two are 20° apart by the end of the month.
Hence Vesta is also an evening object setting shortly after midnight by
the 31st. Vesta´s magnitude drops from 7.9 to 8.2 during December.
(15) Eunomia is in Perseus during December. Having been at opposition on
November 29 it will start to lose brightness in December, its magnitude
changing from 8.0 to 8.6 during the month. The asteroid is quite low in
New Zealand skies, as it will be in Perseus. Early in December it will be
close to the 4th magnitude star xi Per, with Eunomia some 9´ to the right
of the star on the 3rd.
Eunomia will be about 12° below the Pleiades at 11 pm on the 1st. At the
same time on the 31st Eunomia will be about 7° below the cluster, with the
asteroid on the border of Taurus.
(433) Eros, the first Near Earth Asteroid to be discovered, will brighten
to magnitude 9.5 at the end of December. The asteroid will then be a
morning object in Leo rising about 1 am. Watch this space in the New
Year.
More details and charts for these minor planets can be found on the RASNZ
web site. Follow the link to asteroids 2011.
COMETS:
Levy, P/2006 T1 will be only some 5° above the horizon about an hour after
sunset in late December with an expected magnitude about 8. It should
become more visible from the southern hemisphere in the New Year.
- Brian Loader
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