SkyEye

Welcome to SkyEye, your guide to this month's celestial events. All dates are based on Universal Time (UT).

The Sun and Moon

There are no eclipses this month. As seen from the Earth, the Sun is moving from the non-zodiacal constellation Ophiuchus to Sagittarius.

The phases of the Moon are

New : 7 December
First Quarter : 16 December
Full : 22 December
Last Quarter : 29 December

The Moon is at apogee on 8 December and at perigee on 22 December. The coincidence of Full Moon occuring at perigee will mean unusually high tides on Earth.

The Moon occults three planets and one first-magnitude star in December. Like the previous eight months, Neptune and Uranus are occulted a day apart. Neptune goes first on 11 December with the occultation of Uranus the following day. Both events occur during daylight hours. Mars also vanishes behind the limb of the Moon on 12 December at 19 UT. Northwestern parts of Africa can watch this event during the evening. Polar bears again get the chance to witness Aldebaran disappearing behind the Moon on 21 December.

The Planets

The word planet is derived from the Greek word for "wanderer." Unlike the background stars, planets seem to move around the sky, keeping mostly to a narrow track called the ecliptic, the path of the Sun across the stars.
Mercury
Mercury is low in the eastern sky before sunrise for southern hemisphere viewers. It is better placed for observation in the northern hemisphere but soons begin to dip back towards the Sun. Mercury can be found in the constellations of Libra, Scorpio, Ophiuchus, and Sagittarius.
Venus
Now the "morning star," Venus is well-placed to be seen by early risers in both hemispheres. Look for it in the constellations of Virgo and Libra.
Mars
Mars is occulted by the waxing Moon on 12 December and can be found close to Uranus in the sky two days later. The red planet reaches solstice on Christmas day. Mars sets mid-evening in the constellation of Capricornus.
Jupiter
The largest of the planets begins prograde motion on 21 December. It sets after midnight in the constellation of Pisces.
Saturn
Saturn rises just after Jupiter in the constellation of Aries.
Uranus
Uranus sets in the constellation Capricornus just before Mars disappears below the horizon. On 12 December, Uranus is occulted by the Moon and two days later it has a close encounter with Mars.
Neptune
Neptune is falling behind Uranus after their triple conjunction in 1993, but they are still found close together in the sky. Like Uranus, Neptune also is occulted by the Moon, this time on 11 December. It is in the constellation of Capricornus.
Pluto
Pluto is at conjunction on 2 December and is too close to the Sun to be seen this month.

Minor Planets, Comets and Meteors

Minor Planets
A number of interesting minor planets populate the solar system.
Comets
There are no periodic naked-eye comets visible this month, but the fragmented comet Machholz 2-A reaches perihelion on 7 December. You will need a telescope to see it as it moves from Aquila to Aquarius and Capricornus.
Meteors
There are four interesting meteor showers this month. New Moon coincides with the peaks of two southern hemisphere showers, the Phoenicids on 6 December and the Puppid-Velids on 7 December. The usually reliable Geminids peak on 14 December. The Moon sets by midnight so there should be minimal lunar interference. Unfortunately, the Ursids on 22 December will probably be completely washed out by the bright Full Moon.

The Celestial Sphere

Constellations are patterns of stars in the sky. The International Astronomical Union (IAU) recognizes 88 different constellations. The brightest stars as seen from the Earth are easy to spot but do you know their proper names? With a set of binoculars you can look for fainter objects such as nebulae and galaxies or some of the closest stars to the Sun.

Descriptions of the sky for observers in both the northern and southern hemispheres are available for the following times this month. Subtract one hour from your local time if daylight savings time is in effect. (Note: These times are approximate.)

Northern Hemisphere : 45° N

Southern Hemisphere : 30° S

For More Information...

Blue moons, eclipses, the dates of Easter and much more can be found at the Interactive Astronomy Pages. For more information about the objects and events described in SkyEye, visit these astronomy-related sites.

Credits

Much of this information can be found in this month's issue of Sky & Telescope and in other fine amateur astronomy magazines available in your local bookshop. Another excellent source is the current edition of the Astronomical Calendar by Guy Ottewell and published by the Universal Workshop at Furman University.

The image of the Sun in the SkyEye banner is courtesy of the SOHO/EIT consortium. SOHO is a project of international cooperation between ESA and NASA.

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