Skywatch Line for Wednesday, October 21st and Thursday, October 22nd

This is the Dudley Observatory Skywatch Line for Wednesday, October 21st and Thursday, October 22nd written by Louis Suarato

Wednesday evening, after sunset, the 62% waxing gibbous Moon will be 32 degrees over the southern horizon. Saturn will be setting to the Moon’s lower right, over the southwestern horizon. In between the Moon and Saturn, is the constellation Sagittarius and the Milky Way, replete with deep sky objects. A binocular or telescope scan of this area, from an altitude of 16 degrees to the southwestern horizon, will reveal the Eagle, Omega, Trifid, and Lagoon nebulae. Intertwined between these nebulae are the open clusters M25, M23, M22 and M21.

October 22nd is the birth date of American physicist and radio engineer, Karl Jansky. Jansky, born in 1905, discovered radio waves emanating from the Milky Way in August 1931. While working at Bell Telephone Laboratories, Jansky built an antenna designed to receive radio waves. While recording and categorizing these radio waves for months, Jansky discovered that the strongest radio waves repeated every 23 hours and 56 minutes, the time period of the Earth’s complete rotation relative to the stars, or sidereal day. Jansky concluded that the strongest signal originated from the center of the galaxy, within the constellation Sagittarius. Radio Astronomy has led to discoveries beyond the capabilities of visual astronomy, including cosmic microwave background radiation, regarded as evidence for the Big Bang theory.

The constellation Orion can be seen above the eastern horizon before midnight. The Orionid Meteor Shower peaks Wednesday night but the best time to observe will be Thursday before dawn, after the Moon sets. The meteors from this shower originate from debris left by Halley’s Comet. The radiant for the Orionids is to the east of Orion, left of Betelgeuse, the star at the shoulder of The Hunter. Expect to see 10 to 20 meteors per hour, depending on the darkness conditions in your area.

Thursday morning’s sky also features the planets Venus, Jupiter and Mars in the east. The three planets are now separated by 5 degrees. Venus shines brightest at magnitude -4.6, followed by Jupiter at -1.8 and Mars at 1.8 magnitude.

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