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This is the Griffith Observatory Sky Report through March 21st, 2018. Here’s what’s happening in the skies of southern California.

Spring begins in the northern hemisphere at 9:15 a.m., PDT on the 20th. This is the March equinox, and it also marks the start of autumn in the southern hemisphere. It is the moment at which the sun crosses the celestial equator, moving from south to north, and a date on which most places on Earth experience approximately equal amounts of day and night. Spring will end with the solstice on June 21st, the start of summer in the northern hemisphere.

Venus, the brightest planet, is visible above the western horizon at sunset. Thirty minutes after sunset, the sky becomes dark enough to also see the innermost planet, Mercury. Mercury is easy to spot a few degrees to the right of Venus. Before the 20th, Mercury is higher in the sky than Venus. On the 20th, it is slightly lower than Venus, but after that, it will probably be too faint to see. Use a telescope to see Mercury’s crescent phase.

The brilliant planet Jupiter, in the constellation Libra the Scales, gleams from low in the east-southeast beginning shortly before midnight, and when dawn starts, it has moved to a position high in the south-southwest sky.

Orange Mars and Golden Saturn, are bright and visible to the lower left of Jupiter in the south-southeast portion of the sky at 6:00 a.m. Mars appears to be closing in on Saturn morning by morning; between the 14th and 21st the gap between them shrinks from 9 to 6 degrees. From a dark sky, where the Milky Way can be seen easily, binoculars will be able to show a beautiful view of Mars against the backdrop of the Milky Way, and located between the bright Messier objects M20, the Triffid Nebula, and M8, the Lagoon Nebula. Charles Messier was the astronomer who catalogued them in the 18th century. M8 and M20 both appear as hazy clouds surrounding clusters of stars. The word nebula is the Latin word for cloud, and these nebulae are regions in our galaxy where we witness clusters of stars forming from vast clouds of gas.

The moon is new on the 17th. It can be spotted above the east-southeast horizon just before sunrise through the 15th. It returns to view in the evening sky on the 18th, when it is located to the left of Venus and Mercury. It appears higher in the sky on following nights, and by the 21st, the waxing crescent sets at 11:34 p.m.

The International Space Station passes above Los Angeles before sunrise on Sunday, March 18th. The ISS crosses the sky from the northwest to the southeast between 6:22 and 6:28 a.m., PDT. It will outshine anything else in the sky when it appears nearly overhead at 6:25 a.m.

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, March 24th.

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