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This is the Griffith Observatory Sky Report through the period ending October 9th, 2020. Here’s what’s happening in the skies of southern California.
The planet Mars reaches its closest point to Earth on October 6th, when it is 38.6 million miles away. This will be the closest approach between Earth and Mars since 2018. Unlike that close approach, Mars appears much higher in the sky this time for northern hemisphere observers. For observers with access to telescopes, the atmosphere of Mars is unusually clear, also unlike the close approach in 2018 when the surface of the planet was hidden under a global dust storm.
Mars is the brightest object in the evening sky, after the moon, and its orange gleam should be easy to find above the eastern horizon by 9:00 p.m. It crosses the meridian very high in the sky— 62 degrees above the southern horizon—at about 1:20 a.m., and it is still visible, low in the western sky, at dawn. Mars will be at opposition (at the point directly opposite to the sun) on the 13th.
Mars will be well positioned for viewing through any well-adjusted astronomical telescope each night between 10:00 p.m. and 5:00 a.m., over which time the planet completes more than a quarter of a rotation. Because the rotation period of Mars (a sol) is 39 minutes longer than our 24-hour day, the face of Mars visible at any given time changes slightly from one night to the next, so all of the planet may be examined through a telescope from any location on Earth over a period of about five weeks. With a magnification of about 80-power, Mars will appear to match the size of our unmagnified moon.
The waning gibbous moon, a day past full, will appear next to Mars as the sky grows dark on October 2nd. The moon’s phase diminishes to last-quarter on the 9th. The time of moon rise changes from 7:25 p.m. to 11:56 p.m. over this period.
During evening twilight, the bright planets Jupiter and Saturn are visible to the south. Jupiter is the brightest member of the pair, and the position of Saturn is to the upper left of Jupiter. Jupiter sets at midnight.
The brightest planet, Venus, blazes in the east by about 4:30 a.m. On October 2nd, Venus will appear only ½ degree above the bright star Regulus in the constellation Leo the Lion. Twelve hours later observers in Asia will get a spectacular view of Venus and Regulus when they appear six times closer together. This close pairing, an appulse, is only a chance alignment; at the time of the appulse, Venus is 9 light minutes away, while Regulus is 78 light years beyond.
On the 3rd, Venus will still be less than a degree from Regulus, but below the star. By the 9th, the angular separation of Venus below Regulus will have grown to nearly eight degrees.
As darkness falls on October 8th, be on the lookout for possible activity from the Draconid meteor shower, associated with the short-period comet 21P/Giacobini-Zinner. If a shower occurs, meteors will appear to stream from the head of the constellation Draco the Dragon, located high in the southwest when the sky darkens at 7:45 p.m. Prospects for this happening, however, are very uncertain, but as Draconids sometimes produce great numbers of meteors, it might be worth checking the sky that evening.
Because of measures in place that are intended to reduce the spread of the COVID-19 Corona virus, Griffith Observatory remains closed until further notice. Please check the Griffith Observatory homepage for current information and continued updates of the situation.
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From Griffith Observatory, I’m Anthony Cook, and I can be reached at Anthony.Cook@lacity.org.