The Sky Calendar is provided by Starry Night Education with contributions by Larry Sessions and Geoff Gaherty.

Moon Phases

The Moon is not visible on the date of New Moon because it is too close to the Sun, but can be seen low in the east as a narrow crescent the morning before, just before sunrise. It is visible in the low southwest the evening after New Moon.

The First Quarter Moon rises around noon, and sets around 1 a.m.

The Full Moon of December is usually known as the Oak Moon. In Algonquian it is called Cold Moon. Other names are Frost Moon, Long Night?s Moon and Moon Before Yule. In Hindi it is known as Margashirsha Poornima. Its Sinhala (Buddhist) name is Unduvap Poya. The Full Moon rises around sunset and sets around sunrise, the only night in the month when the Moon is in the sky all night long. The rest of the month, the Moon spends at least some time in the daytime sky.

The Last or Third Quarter Moon rises around midnight and sets around 11 p.m. It is most easily seen just after sunrise in the southern sky.

Observing Highlights

This morning Venus will be at its most brilliant, exposing the largest area of sunlit clouds of the current apparition. Two things are going on. The illuminated crescent of Venus is getting larger, percentage wise, as the planet moves towards full sunshine. At the same time, Venus is receding from the Earth, and so getting smaller in diameter. On this date the two balance out, giving Venus its greatest illuminated extent, and making it appear at its brightest, magnitude ?4.9.

The radiant of the Geminid meteor shower, close to Castor in Gemini, is above the horizon all night. The peak of the shower is at 6 a.m. Tuesday morning. The number of meteors observed always increases after midnight because Earth is heading into the meteoroid stream, so the best views will be from midnight to dawn. This is one of the best meteor showers in the year, worth braving the cold to watch.

The first hint of the shadow of the Earth falling on the Moon occurs at 29 minutes past midnight EST (9:29 p.m. PST). The umbra, the darkest part of the Earth?s shadow, begins to encroach on the Moon at 1:32 a.m. EST/10:32 p.m. PST. Maximum eclipse is at 3:17 a.m. EST/12:17 a.m. PST. The umbra leaves the Moon at 5:01 a.m. EST/2:01 a.m. PST, and the eclipse ends at 6:05 a.m. EST/3:05 a.m. PST.

Planets

Mercury will be an ?evening star? at the very beginning of the month, but will be too close to the Sun to observe for the rest of the month. This is an unfavorable apparition for observers in the northern hemisphere, but a good one for southerners.

Venus? is a brilliant ?morning star? all month. It reaches greatest brilliancy on December 4.

Mars is pretty much lost in evening twilight, on the far side of the Sun.

Jupiter is well placed all evening, dominating the southern sky. It is in the constellation Aquarius for the first half of the month, moving into Pisces on December 17. It sets around midnight.

Saturn is now a morning ?star? in Virgo. Its rings have returned to their usual glory after being on edge for the last two years.

Uranus is in Pisces all month, and remains within a few degrees of Jupiter.

Neptune is in Capricornus and sets around 10 p.m.

The Sky Calendar is provided by Starry Night Education, the leader in space science curriculum solutions.