Sky Report

December, 2022

This is the Griffith Observatory Sky Report for the period between December 1 and December 31, 2022. Here are the events happening in the sky of southern California.

Mercury sets at 5:26 p.m., PST, on the 1^st, and the sun sets at 4:44 p.m., PST.  Mercury’s disk is 93-percent illuminated and only five arcseconds wide. On the 31^st, the sun sets at 4:54 p.m. PST, and Mercury sets at 5:57 p.m., PST. Mercury’s disk is 16-percent illuminated and nine arcseconds wide. Do not observe any planet when it appears close to the sun, for the danger to the eyes is great.

Venus sets at 5:20 p.m., PST, on the 1^st. Venus’s disk is 99-percent illuminated and ten arcseconds wide. On the 31^st, Venus sets at 6:10 p.m., PST, with a disk that is 96-percent illuminated and ten arcseconds wide. Do not observe any planet when it appears close to the sun, for the danger to the eyes is great.

Mars is in Taurus the Bull.  On the 1^st, Mars rises at 5:02 p.m., PST, with a disk that is 100-percent illuminated and 17 arcseconds wide. Mars increases in brightness and diameter as it approaches opposition with the sun on December 7^th at 9:42 p.m., PST. On the 31^st, Mars rises at 2:24 p.m., PST, with a disk that is 97-percent illuminated and 15 arcseconds wide.  A telescope capable of magnification of 100x or more will be needed to show the disk and any large surface features.

Jupiter is in Pisces the Fishes. On the 1^st, Jupiter sets at 1:09 a.m., PST, and on the 31^st at 11:18 p.m., PST. Jupiter’s disk is 40 arcseconds wide on the 15^th. A telescope capable of magnification 50x will show the Red Spot and the four bright Galilean moons, which can be seen moving back and forth, roughly in a line centered on Jupiter.

Saturn is in Capricornus the Sea Goat. On the 1^st, the planet sets at 9:58 p.m., PST, and on the 31^st at 8:12 p.m., PST. The rings and Saturn’s largest moon Titan can be seen with a telescope capable of magnification 50x.

Uranus is in Aries the Ram. On the 1^st, the planet sets at 4:55 a.m., PST, and on the 31^st at 2:53 a.m., PST. On the 15^th, Uranus is at Right Ascension 2^h 52^m 51^s with a declination of +16° 9ʹ 11ʺ. Uranus is 3.7 arcseconds wide, and so a telescope with a magnification of 150x is needed to show its diminutive disk.

Neptune is in Aquarius the Water Bearer. On the 1^st, the planet sets at 12:39 a.m., PST, and on the 31^st at 10:38 p.m., PST. On the 15^th, Neptune is at Right Ascension 23^h 35^m 0^s and declination -4° 0ʹ 13ʺ. Neptune is 2.3 arcseconds wide, and so a telescope with a magnification of 150x is needed to show its diminutive disk.

Full moon occurs on the 7^h, last quarter on the 16^th, new moon on the 23^rd, and first quarter on the 29^th.

SPECIAL EVENTS

An occultation of Mars by the moon will occur at 6:31 p.m., PST, on December 7. The moon will pass in front of Mars as viewed from Los Angeles. Mars is at an azimuth of 74 degrees and an elevation of 23 degrees. Mars emerges from behind the moon at 7:31 p.m., PST, at an azimuth of 81 degrees and an elevation of 35 degrees. Mars will appear on the limb of the moon for only 30 seconds.  A telescope with a magnification of 50x or more will be needed to see the small disk of Mars on the limb of the moon.

The winter solstice occurs on December 21 at 1:48 p.m., PST. The sun reaches its southernmost point on the ecliptic, reverses its movement south, and heads north.  This marks the longest night and the shortest day of the year. The sun rises at 6:55 a.m., PST, and sets at 4:48 p.m., PST.  The day is 9 hours 53 minutes long.

The Geminid meteor shower is active from December 4 to 17, with the peak occurring from the evening of the 13^th through the morning of the 14^th. The approximate peak hour is from 1:23 a.m., PST, to 2:23 a.m., PST. The expected dark-sky rate is 150 meteors per hour, but rates will be significantly decreased by bright moonlight after 9:54 p.m., PST. The shower’s radiant is close to the bright star Castor in the constellation Gemini the Twins.

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