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This is the Griffith Observatory Sky Report for the period between October 1 and October 31, 2021. Here are the events happening in the sky of southern California.

Mercury starts the month in the evening sky. On October 1, the sun sets at 6:37 p.m., PDT, and Mercury sets at 8:06 p.m., PDT. Within a few days the planet is too close to the sun to be observed. During the last two weeks of October Mercury appears in the morning sky. The planet reaches greatest western elongation on the 25^th. Mercury is then farthest from the sun. On that date, the planet rises at 5:37 a.m., PDT, and the sun rises at 7:07 a.m., PDT. Never observe Mercury when the sun is in the sky, for the risk of damage to the eyes is great.

Venus is in the evening sky. On the 1^st, the planet sets at 8:35 p.m., PDT. On the 31^st, the sun sets at 6:01 p.m., PDT, and Venus sets at 7:33 p.m., PDT. The planet offers a small disk and appears as a half-phase when viewed through a telescope. Venus slowly increases in size from 19 arcseconds to 26 arcseconds, while at the same time the gibbous phase slowly gets thinner, from 62 percent to 48 percent. On the 29^th, Venus is at greatest eastern elongation. The planet then appears farthest from the sun.

Mars is close to the sun and unobservable until mid-November, when it appears in the morning sky.

Jupiter sets at 3:09 a.m., PDT, on the 1^st, and on the 31^st it sets at 1:14 a.m., PDT, and so it will be visible all evening. A telescope will reveal features on the disk and the four Galilean moons, which travel in a rough line east to west across and behind Jupiter.

Saturn sets at 1:53 a.m., PDT, on the 1^st, and on the 31^st the planet sets at 11:59 p.m., PDT. The planet is well placed for observations in the evening sky. A telescope will reveal Saturn’s disk, its rings, and perhaps its brightest and largest moon, Titan.

Uranus is at Right Ascension 2^h 43^m 49^s, declination +15° 24ʹ 59ʺ on the 15^th. The disk of Uranus is only 3.8 arcseconds wide, and so a telescope of magnification 150x is needed to show it.

Neptune is at Right Ascension 23^h 27^m 31^s, declination 4° 46ʹ 34ʺ on the 15^th. The disk of Neptune is only 2.4 arcseconds wide, and so a telescope with a magnification of 150x is needed to show it.

New moon occurs on the 6^th, first quarter on the 12^th, full moon on the 20^th, and last quarter on the 28^th.

SPECIAL EVENTS

The Orionid meteor shower peaks from the night of October 20^th through the morning of October 21^st. It is named after the constellation of Orion the Hunter, where the meteors appear to originate. The Orionids usually produce 10 to 20 meteors per hour, but the full moon will interfere with observations.

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