What's Up in the Night Sky

December 2022 - Vol. 26, 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 Aldeberan, 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 emerges in the evening sky mid-month and will be in conjunction with Venus on the 29th, favoring the southern hemisphere. Binoculars will be needed, but you must be careful to avoid the Sun if you are observing. VENUS slowly emerges in the evening twilight. MARS is at opposition in Taurus shining at -1.8 mag on December 8. Mars will be occulted by the Moon at 4 UT. Check the monthly topic on this page for more details. Astra's Stargate is proud to present our first video simulating the occultation in Stellarium the open source planetarium program we prefer at the 'Gate. JUPITER is prominent in the evening sky, setting around midnight. SATURN, in Capricornus, sets in the evening sky. URANUS has another occultation with the Moon on the 5th. NEPTUNE is in Aquarius, setting around midnight.

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
01	Mars at closest approach, .544 AU away from Earth Juno 1.2 deg. S. of Moon, occultation from W. USA, Alaska, most of Canada. Neptune 3 deg. N. of Moon.
02	Jupiter 3 deg. N. of Moon.
04	Neptune stationary.
05	Uranus 0.7 deg. S. of Moon, occultation from most of N. Africa, Azores, Europe, parts of Middle East, Russia, N. Japan.
08	Mars at opposition. Mars 0.5 deg. S. of Moon, occultation from NW Mexico, Most of USA, Canada,Greenland, Svalbard, Europe, W Russia, parts of N Africa.
10	Mercury at greatest heliocentric lat. S.
11	Alpha Geminorum, Pollux, 1.8 deg. N. of Moon.
12	Moon at apogee. Jupiter at greatest heliocentric lat. S.
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 showers and may produce about 120 meteors per hour at its peak. Best observed after midnight.
21	Solstice, Summer in the southern hemisphere, Winter in the north. Mercury at greatest elongation E.
22	Ursid meteor shower produces 10 meteors at its peak, that is at 22 UT.
24	Moon at perigee, expect large tides. Venus 3 deg. N. of Moon. Mercury 4 deg. N of Moon.
26	Venus at aphelion. Saturn 4 deg. N. of Moon.
28	Neptune 3 deg. N. of Moon.
29	Mercury at ascending node. Mercury stationary. Mercury 1.4 deg. N of Venus. (As always take proper precautions observing near the Sun.) Jupiter 2 deg. N. of Moon.

Lunar Almanac for December 2022

Phases of the Moon	Phase and Date(s)	Best viewed before local midnight
	New 23	Deep Space Objects
	1st. Qtr 29	Planets & Moon
	Full 07	Moon
	Last Qtr 16	Deep Space & Planets

Topic of the month: Mars 2022 opposition in Taurus

Mars is in Taurus for the 2022-23 opposition that occurs on December 8, 2022. Mars appears to race through the sky as it approaches opposition, but must slow down and reverse its track as Earth begins to overtake it. The red planet will stay in Taurus until the last week of March 2023 when it moves into Gemini. Taurus is considered a fall constellation by observers in the northern hemisphere. The bright star, Aldebaran, the open star cluster known the Pleiades (M-45), and the Hyades open star cluster are bright features of this constellation

This year's Mars opposition takes place in Taurus where the red planet will ride high in the sky. During opposition, Mars is in a constellation that is opposite where the Sun is. Northern winter hits on the solstice, and that is when the sun is in the south. Unfortunately, Mars will be farther from the Earth in during the next few oppositions. This means the disk of Mars is smaller. In 2003, the year that Mars and Earth made a very close passage, the red planet was a mere 35 million miles away, when its disk was 25.11 arc secs. When Mars is at its closestapproach on December 1, it will be 38.6 million miles away with a disk diameter of 17.0 arc secs.

But this apparition of Mars brings an exciting opportunity. It occurs near full moon and the full large lunar disk will pass between Earth and Mars. Mars will not be visible as the Moon blasts been the planets. The lunar occultation occurs at 4h UT, but local time at an oberving site will be somewhat different. This occultation will be visible for many observers in the northern hemisphere. Many locations in the Europe, the United States and Canada will be able to view this occultation. For most observers in the US and Canada, the occultation occurs on the night of the 7th, before midnight. Make sure you are ready at the right time.

Mars at opposition December 08, 2022 — Mars opposition December 08, 2022 occurs at 6 UT

For this month's almanac, Astra's Stargate is presenting a video showing the lunar occultation of Mars that occurs on the night of opposition, at 4 hours UT. This is the first video created for Astra's but we are hoping it won't be the last. Enjoy the show!

Occultations are very important to astronomers. Especially before the space age when distances to solar systems planets were still being studied. Today occultations are used to study asteroids. Information about those small bodies can be gathered when an asteroid in front of a distant star. Timing of the occultation passage from various location on Earth require accurate measurements and highly coordinated efforts. Another method is used for binary asteroids. This is how NASA and astronomers determined that the DART mission was successful. Because of the Didymos-Dimorphos binary asteroid is well aligned with Earth, watching for the system to dim when the smaller asteroid moved in front of the parent enabled astronomers to measure the orbit.