This is the monthly Griffith Observatory Sky Report.
This is the Griffith Observatory Sky Report for the period between September 1 and September 30, 2023. Here are the events happening in the sky of southern California.
Mercury sets three minutes after the sun sets on the 1st and is unobservable. On the 9th, Mercury rises due east at 6:09 a.m., PDT, and the sun rises at 6:32 a.m., PDT, 23 minutes later. On the 30th, Mercury rises at 5:37 a.m., PDT, and the sun rises at 6:47 a.m., PDT, one hour ten minutes later. The planet’s disk is six arcseconds wide, and a magnification of 200x is needed. Do not observe any planet when it comes close to the sun, for the danger to the eyes is great.
Venus rises north of east at 4:33 a.m., PDT, on the 1st. The sun rises at 6:27 a.m., PDT, one hour and 54 minutes later, and so Venus is observable. On the 30th, Venus rises in the east at 3:23 a.m., PDT, and the sun rises at 6:47 a.m., PDT, three hours and 24 minutes later. Venus is 36-percent illuminated and 32 arcseconds wide.
Mars is in Virgo the Maiden on the 17th. On the 1st, the sun sets at 7:19 p.m., PDT, and Mars sets in the west at 8:24 p.m., PDT, one hour five minutes later. The planet’s disk is only 3.8 arcseconds wide and so is too small to be seen in most telescopes. On the 30th, the sun sets at 6:39 p.m., PDT, and Mars sets at 7:19 p.m., PDT, 40 minutes later. The disk of Mars will remain small until a few months before January, 2025, the time of the planet’s next opposition.
Jupiter is in Aries the Ram. On the 1st, Jupiter rises north of east at 10:18 p.m., PDT. On the 30th, Jupiter rises at 8:20 p.m., PDT, and the planet is 48 arcseconds wide. A magnification of 50x will show the Red Spot, and the four bright Galilean moons may be seen moving back and forth, roughly in a line centered on Jupiter.
Saturn is in Aquarius the Water Bearer. On the 1st, the planet rises south of east at 7:04 p.m., PDT. On the 30th, Saturn rises at 5:04 p.m., PDT. Saturn is 19 arcseconds wide. A magnification of 50x is needed to see the rings and Saturn’s largest moon Titan.
Uranus is in Aries the Ram. On the 1st, Uranus rises north of east at 10:38 p.m., PDT, and at 8:42 p.m., PDT, on the 30th. On the 15th, Uranus is at Right Ascension 3h 21m 14s and declination +18° 6ʹ 58ʺ. A magnification of 200x is needed to see its 3.7-arcsecond-wide disk.
Neptune is in Pisces the Fishes. On the 1st, the planet rises south of east at 8:03 p.m., PDT. On the 30th, Neptune rises at 6:07 p.m., PDT. On the 19th, Neptune is at opposition and is closest to earth. On the 15th, Neptune is at Right Ascension 23h 47m 34s and declination -2° 44ʹ 12ʺ. A magnification of 200x is needed to see its 2.3-arcsecond-wide disk.
Last quarter occurs on the 6th, new moon on the 14th, first quarter on the 22nd, and full moon on the 29th.
Autumn begins and summer ends when the sun reaches the autumnal equinox on the 22nd at 11:50 p.m., PDT. At this moment, the sun crosses the celestial equator from north to south on its journey along the ecliptic. The sun rises at 6:41 a.m., PDT, and sets at 6:50 p.m., PDT. The day is 12 hours nine minutes long. The days will continue to grow shorter, and the nights get longer, until the sun reaches the winter solstice on December 21.
A Lunar-X event happens on Thursday, the 21st, at 8:40 p.m., PDT. Lunar-X is the raised rim of a few craters that are illuminated by the sun. It appears as a white X-shaped feature on the dark half of the first quarter moon, just west of the terminator, the line between the illuminated and the dark portions of the moon. Lunar-X will be visible for a few hours. Binoculars or a small telescope will be needed to see it.