What's Up in the Night Sky

December 2025 - Vol. 29, No. 12

This Month's Night Sky - NOTE: The next paragraph describes the sky as it appears at 10 pm EST (11 pm EDT) near mid- month. The sky also looks this way at 11 pm EST (midnight EDT) during the beginning of the month and at 9 pm EST (10 pm EDT) by month's end.

Some believe the winter night sky is the most beautiful of the year! By mid-month, misty Pleiades, the famous open star cluster of the constellation Taurus, is visible due S. at 10 pm. Although part of the constellation Taurus, it lies above its "lazy V" asterism whose brightest star, orange-tinted Aldebaran, glows near the point of the lower branch of the "V". Above are the constellations Perseus, Cassiopeia (whose "W" shaped asterism is unmistakable) and Auriga. Lovely Orion, whose asterism reminds me of a slightly lopsided hour glass, moves upwards from the SE. Note its three "belt" stars located at the "pinch" of the hour glass. The hazy object below the middle belt star is M42, the Great Orion Nebula, a region of space where stars are being born. Orion is followed by the bright stars Procyon (Canis Minor) and Sirius (Canis Major). Along with the bright star Betelgeuse (Orion), these three stars form the famous "Winter Triangle". To the E shine the Gemini twins, Castor and Pollux. In the SW, the diamond-shaped "Great Square of Pegasus" stands on one corner, while high in the N, Ursa Major's asterism, the Big Dipper, stands on its "bowl".

MERCURY in Libra, shines brightly for the best morning apparition for observers in the northern hemisphere. VENUS is too close to the Sun to be observed this month. MARS, is too close to the Sun to be observed this month. JUPITER rises shortly after sunset, shining at -2.6 magnitude as it approaches next month's opposition. SATURN shines most of the night, located in the constellation of Aquarius. URANUS is up most of the night after last month's opposition. NEPTUNE is located in the constellation of Pisces for observers with a telescope.

Review how to determine Angular Measurement.

Calendar of Events

NOTE: For those observers not in the ET zone, convert the calendar times to your zone's time by subtracting one hour for CT, two for MT and three for PT. Don't forget to adjust for Daylight Savings Time when necessary by subtracting one hour from your planisphere's time. Dawn and dusk times must also be corrected. See your local newspaper, TV news, or cable TV's Weather Channel for sunrise and sunset times or check with the U.S. Naval observatory. Unfortunately some of these events may occur during daylight hours in your area.

DATE	EVENT
04	Moon 0.8 deg. N. of the Pleiades star cluster (M-45). Moon at perigee, expect large tides. Mercury at greatest heliocentric lat. N.
07	Jupiter 4 deg. S. of Moon. Mercury greatest elongation W. (21 deg).
08	Moon 1.4 deg. N. of the Beehive cluster (M-44).
10	Alpha Leonis, Regulus, 0.7 deg. S. of Moon, occultation from most of Canada, E. Alaska, Greenland, Iceland, Europe, Azores, most of N. Africa.
11	Neptune stationary.
14	Geminid meteor peak. This meteor shower is unusual in that it is associated with the 3200 Phaethonan asteroid that orbits the Sun every 1.4 years. Most showers are associated with periodic comets. The Geminid shower is one of the most prolific meteor shower that may produce about 120 meteors per hour at its peak. Best observed after midnight. Alpha Virginis, Spica, 1.4 deg. N. of Moon.
17	Moon at apogee.
18	Alpha Scorpii, Antares, 0.4 deg. S. of Moon, occultation from Easter Island, S. South America, eastern Antarctica, S. tip of Africa.
21	Solstice. Winter begins in the northern hemisphere, Summer in the south.
22	Ursid meteor shower that produces 10 meteors at its peak. Pluto, 0.6 deg. S. of Moon, occultation from Hawaii, most of Central America, most of USA, N. Caribbean, and E. Canada.
27	Saturn 4 deg. S. of Moon. Neptune 3 deg. S. of Moon.
31	Moon 0.9 deg. N. of the Pleiades star cluster (M-45).

Lunar Almanac for December 2025

Phases of the Moon	Phase and Date(s)	Best viewed before local midnight
	New 20	Deep Space Objects
	1st. Qtr 27	Planets & Moon
	Full 04	Moon
	Last Qtr 11	Deep Space & Planets

Topic of the month: Taurus, the Bull

Night falls quickly for North Americans as Autumn turns to Winter and the evening skies darken after sunset. The constellation of Taurus has risen by sunset and crosses the sky all night. Taurus is an ecliptic constellation that has been associated with a bull. The bull shape is rather enigmatic to some, for although constellation maps may show horns, it is difficult to see more than one leg with the face of the bull as it charges across the sky. The first magnitude star Aldebaran marks the eye of the bull, nestled in a triangular shaped group of stars that forms the "face" of the bull. The triangular face of the bull is a very important star cluster, the Hyades. The center of this cluster has been measured by astronomers to be located about 150 light years away from the Earth. The fiery eye of Aldebaran is not a member of the cluster, but resides about midway between our Sun and the Hyades center.

constellation of taurus the bull — Constellation of Taurus the Bull

+ + Astra featured the Hyades cluster in February 2016, What's Up in the Night Sky topic.

Taurus lies across the winter Milky Way from the constellation of Gemini. It contains two famous open star clusters, the Pleiades (M-45), and the previously mentioned Hyades star cluster. The Pleiades cluster is also known as the seven sisters, although only 6 of its estimated 250 stars are bright enough to be seen with the naked eye. Nevertheless, it is the brightest star cluster in our sky. The Pleiades cluster is probably about 445 light-years away from Earth. Taurus contains another famous object, the Crab Nebula (M-1). The nebula is a supernova remnant that contains a type of star called, a pulsar of 16th magnitude.

Taurus will cross the sky until next May, carrying the seven sisters and the head of the bowl from the eastern sky to the western sky, until the Bull plunges into the sunset horizon.

--See You Under the Stars!
Astra for Astra's Almanac

The star chart above was generated by Stellarium, a free open source planetarium program. The above image was created by Dawn Jenkins, using Stellarium and graphic editing programs to format the image for this web page. Editing was done for educational purposes only. Stellarium offers much more to amateur astronomers and is being used in planetariums and to guide telescopes in the field. Simple charts like the one above can be used on the internet for non-profit, illustration purposes. Proper credit is due of course! Thank you to the makers of this fine program from Astra's Star Gate.