Sunrise and Sunset Times
Eastern Standard Time from the U.S. Naval Observatory
Sun rises at 7:04 a.m. and sets at 4:37 p.m. on the 1st
Sun rises at 7:23 a.m. and sets at 4:46 p.m. on the 31st
Moon’s Phases in December
New Moon on the 7th.
Full “Moon Before Yule” or “Long Nights Moon” on the 22nd.
Stars and Constellations
Winter officially commences in the Northern Hemisphere on Dec. 21 at 5:25 p.m. EST. Nevertheless, the trio of stars that make up the “summer” triangle — Vega, Deneb and Altair — is still viewable low in the western sky shortly after it gets dark.
But dominating the night sky in the first part of the evening are the stars of autumn.
One of the most familiar lights of autumn nights, the white star Fomalhaut, is now getting low in the southwest. Fomalhaut and Vega lie at approximately the same distance: 25 light years.
High above Fomalhaut, also toward the southwest, is the box of four stars — Alpheratz, Scheat, Markab and Algenib — making up the Great Square of Pegasus.
And well to lower left of the Great Square is the large constellation Cetus, the Whale, with its two brightest stars, Diphda and Menkar.
Standing high in the south in the early evening hours of December are two ancient constellations of the zodiac: Pisces, the Fishes, and Aries, the Ram. Pisces, which is ensconced between Cetus and Pegasus, consists mainly of faint stars, while Aries, which lies just to the east of Pisces and the Great Square, is highlighted by two moderately bright stars, Hamal and Sheratan. Pisces currently contains the Vernal Equinox, a point which the Sun, traveling along the ecliptic, reaches each year around March 20; this marks the official start of spring in the Northern Hemisphere. The Sun passes through the constellations Pisces and Aries from about March 12 through May 12 of each year.
Standing high in the north is the constellation Cassiopeia, now looking like the letter “M.” Cassiopeia is followed in the northeast by the constellation Perseus, with its two brightest stars, Mirfak and Algol, the latter also known as the “Demon Star” in medieval Arabic culture.
By about 8 p.m., the brilliant star groups of winter can be seen rising in the east. The first star of winter to catch your eye will likely be Capella, the yellow-white star in the constellation Auriga, the Charioteer, as it ascends in the northeast. To the right of Auriga, high in the east, are the stars of Taurus, the Bull, which contains the bright reddish star Aldebaran. Aldebaran appears to be part of the “V” shaped Hyades star cluster, but it is only half as far away as the cluster. Also part of Taurus is the Pleiades, a compact star cluster shaped like a miniature dipper. The Pleiades cluster appears so faint because of its immense distance of 440 light years from our solar system.
The champion of winter constellations is unquestionably Orion, which contains two first-magnitude stars, orange-red Betelgeuse and bluish-white Rigel. By midnight, Orion is high in the south.
Located in the east-northeast between Auriga and Orion are the stars Pollux and Castor in the constellation Gemini. After about 9 p.m., look for Procyon, a yellow-white star in the constellation of Canis Minor to be rising in the east to the lower right of Pollux and Castor. And toward the southeast, below Rigel, you will see the brightest star in the night sky: bluish-white Sirius, the “dog star” in the constellation Canis Major.
Naked-Eye Planets in the Evening and Morning Sky
As December opens, Saturn stands very low in the southwest at dusk, resembling a bright yellowish-white star; it sets by around 6:30 p.m. EST, or less than two hours after the Sun. Toward the end of the month, Saturn vanishes into the twilight glow; it reaches conjunction with the Sun in early January and a few weeks later will reappear in the morning sky.
Mars stands due south at nightfall in early December; it resembles an orange star similar in brightness to Vega or Capella. Mars is now nearly three times further away from Earth than it was back in July, and it will continue to fade as Earth pulls away from it. Mars sets at around 11:30 p.m. EST during December.
Early morning risers with a window facing east will be greeted by a beautiful beacon in the sky this December — the planet Venus. There is no mistaking this magnificent light in the sky, as it outshines all other nighttime objects except for the Moon. At midmonth, Venus rises around 3:30 a.m., a full two hours before the onset of twilight and over 3½ hours before sunrise. About an hour after it rises, Venus will be high enough to clear most obstructions on the horizon, and its brilliance will be all the more apparent against the still dark pre-dawn sky.
During December, Mercury climbs into excellent position for viewing in the morning sky. Saturn reaches greatest elongation with the Sun on the 15th, when it rises in the southeast by 5:30 a.m., just before the start of morning twilight. As a bonus, Mercury is in conjunction with Jupiter on the morning of Dec. 21, the winter solstice, when the two planets will be less than 1 degree apart.
Jupiter reached conjunction with the Sun on Nov. 26, and as December opens, it is still lost in the Sun’s glare. By the second half of December, however, Jupiter will reappear in the dawn sky; it passes close to Mercury on the 21st.