Don't forget to watch for flying Orionid meteors tomorrow morning before dawn. This annual shower peaks Sunday Oct. 21 when up to 25 meteors per hour originating from the constellation Orion might be visible from a dark sky site. No moon will mar the view. Head out around 4 a.m. and face south. I encourage you to share your observations in the comment section below.
While you're out meteor watching, check to see if any of the Iridium satellites are visible from your location. The Iridiums , a group of some 66 satellites orbiting the Earth in a global 'constellation' 485 miles high, are used for relaying voice and data communications.
Normally Iridiums are too faint to see except in binoculars, but they have silver-coated Teflon antenna arrays that reflect sunlight like a mirror. When the angle between satellite and observer is right, a brilliant reflection of the sun from the antennas causes an Iridium to suddenly and spectacularly brighten for 5 to 20 seconds. For Duluth, Minn., the city dear to my heart, a -2 magnitude flare (bright as Jupiter) occurs at 5:36 a.m. tomorrow morning just below Orion's Belt.
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Flares range in brightness from equal to the brightest stars all the way up to -8 or about 20 times brighter than Venus. They're very exciting to see. The new maps at Heavens Above make finding where and when to look a snap. Log in, select your city and then click the Iridium Flares link. You'll be shown a table of times and brightness. Just click the time to see the map.
There's also a chance for a small display of aurora borealis for the northern U.S. tonight through Monday as a high speed stream of solar wind particles buffets Earth's magnetic field. If auroras show, they're usually brightest around midnight - 1a.m. Keep an eye out while you're meteor watching.
And don't forget the moon, especially if you're out early this evening.
Binoculars are excellent for bringing out the bigger craters and dark impact basins (lunar seas). Look along the lunar terminator, the arc-shaped border between day and night where shadows are longest and details most clearly defined, for best viewing.
