CSTA Classroom Science

California Skies, Winter 2022

Coming events, December 2022 and beyond: Occultations of Mars by the Moon will be visible in parts of the U.S. on the evenings of Dec. 7 (a Full Moon, the next one after the eclipse), and January 30 (a waxing gibbous Moon). From Los Angeles and Palm Springs on Wednesday, December 7, the Moon covers Mars from 6:30 p.m. until 7:30 p.m. PST. Alert friends in other locations to this rare and spectacular event; for a map of the December 7 occultation with times for many cities, visit  http://lunar-occultations.com/iota/planets/1208mars.htm  and scroll down to the data for U.S. cities. Remember to subtract the appropriate number of hours from Universal Time to convert event times to the observer's timezone: Five hours to get EST, eight hours to get PST.

It happens that Earth overtakes Mars on the evening of December 7, and the planet appears at opposition. From October 30, 2022 until January 12, 2023, Mars appears to retrograde, or move backward or westward against the background stars of Taurus, the Bull. For charts depicting the apparent motion and its explanation, see MARS_retrograde_2022-2023.pdf and Mars_orbit_chart_Conjs_in_geoc_long_2022-23.pdf.

If you didn’t catch the five bright planets simultaneously in morning twilight in June, you'll have another chance in December, this time in evening twilight. Venus and Mercury will then be visible only low in bright twilight, so binoculars will make the search easier. The Sky Calendar for December, attached to this message, has many diagrams helpful for locating Venus and Mercury soon after sunset. Saturn, Jupiter, and Mars will be easy for the unaided eye. Uranus and Neptune will be available for binoculars and telescopes after twilight ends, bringing the total to all seven planets observable sometime within a one-hour span from early dusk until nightfall. 
Here is an evening mid-twilight chart for December 2022, when all five bright planets will be visible for much of the month. [Select the chart S202212P.pdf for southern California, or N202212P.pdf for northern California.]

See the December 2022 Sky Calendar for a selection of daily illustrations and more information. The chart, December Evening Skies, shows the sky later in the evening, after Mercury and Venus have set and after Sirius has risen. Note Orion's 3-star belt points downward to the Dog Star, Sirius. Can you see the Winter Triangle of Betelgeuse, Procyon, and Sirius in east to ESE, while you are still following the Summer Triangle of Vega, Deneb, and Altair in NW to west? There is a narrow window of time when you can view both triangles, after Sirius has risen and before Altair sets.

After December, Venus improves to become a prominent evening "star", setting after the end of twilight from mid-January until early July. On several occasions, Venus will appear close to another planet, a star, or the Moon, as indicated on the graph of Venus' setting times: 2022-23_Venus_evening_apparition.pdf

The close pairings of Venus-Saturn on January 22, Venus-Jupiter on March 1, and Venus nearest to Pleiades star cluster on April 10 and 11 will be especially rewarding to follow for several days before and after, as daily changes will be easily noticed.

Monthly charts showing the sky at evening mid-twilight for the rest of Venus’ evening apparition through July 2023 appear on the Sky Calendar Extra Content Page, at https://www.abramsplanetarium.org/msta/ 



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Written by Robert C. Victor

Robert C. Victor was Staff Astronomer at Abrams Planetarium, Michigan State University. He is now retired and enjoys providing skywatching opportunities for school children in and around Palm Springs, CA. Robert is a member of CASE.


Written By Robert D. Miller

Miller did graduate work in Planetarium Science and later astronomy and computer science at Michigan State University and remains active in research and public outreach in astronomy.

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