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This is the Griffith Observatory Sky Report through December 21st, 2016. Here’s what’s happening in the skies of southern California.

The winter solstice occurs at 2:44 a.m., PST, on the 21st. It is the start of winter in the earth’s northern hemisphere and the start of summer in the southern, and is the result of the 23½ degree tilt of earth’s rotation axis to the plane of earth’s orbit around the sun. From the northern hemisphere, the winter solstice is the moment when the sun reaches its southernmost point in the sky, and is the date of the shortest day. At Los Angeles, the first day of winter is only 9 hours and 53 minutes long. The winter season will end with the vernal equinox on March 20, 2017. Free public events at Griffith Observatory will mark the solstice noon, 11:52 a.m., and sunset, at 4:48 p.m.

Brilliant planet Venus, obvious in the southwest sky after sunset, can help you identify the innermost planet Mercury and the red-hued planet Mars. Start looking for the two fainter planets at about 5:15 p.m.  Mercury is close to the southwest horizon, to the lower right of Venus, while Mars is to the upper left of Venus in the south-southwest sky.  Mars moves from the constellation Capricornus the Sea Goat to Aquarius the Water Bearer on the 16th.

The phase of the moon changes from waxing gibbous on the 14th to last quarter on the 20th. The time of moonrise advances from 6:00 p.m. on the 14th to 12:03 a.m. on the 21st.

The bright planet Jupiter, in the constellation Virgo the Maiden, rises above the eastern horizon by 1:45 a.m., and is 40 degrees high in the southeast sky at 5:21 a.m., when dawn starts. The bright white star located eight degrees east of Jupiter is Spica, Virgo’s brightest star.

The International Space Station will appear high above Los Angeles on the evening of Tuesday the 20th. The ISS will rival the brilliance of a bright planet as it crosses the sky from the northwest to the southeast between 5:37 and 5:44 p.m. The space station is highest in the sky at 5:41 p.m., when it is 63 degrees above the southwest horizon.

An outburst of meteors known as the Alpha Lyncids is possible just before dawn on December 20, according to a prediction made in 2003 by meteor expert Peter Jenniskens. If the outburst occurs, the radiant of the meteors will be within the boundaries of the faint constellation Lynx, located between Ursa Major the Great Bear, and Gemini the Twins. Lynx is situated high in the northwest sky before dawn. The possibility of meteor activity is based on the analysis of a single report of a two hour-long shower of bright meteors observed from England in 1971. Sunrise occurs close to the most likely time of the outburst, 6:45 a.m., but because the exact time of peak activity, if any, is uncertain, observers should start monitoring the sky at about 4:30 a.m. or earlier until dawn.

Free views of the Sun during the day and of the Moon, planets, and other celestial objects at night are available to the public in clear weather through Griffith Observatory’s telescopes from Tuesday through Sunday, before 9:30 p.m. Check our website for the schedule. The next free public star party on the grounds of Griffith Observatory, hosted by the Los Angeles Astronomical Society, the Sidewalk Astronomers, and the Planetary Society, will take place on Saturday, January 7th from 2:00 p.m. until 9:30 p.m.

Follow the Sky Report on Twitter for updates of astronomy and space-related events.

From Griffith Observatory, I’m Anthony Cook and I can be reached at griffithobserver@gmail.com