For October 2020, all eyes will be on bright red Mars at opposition! This is the closest to us Mars has been since August 2003, and telescopic views should reveal interesting meteorology! The earth overtakes it on October 9th, and Mars for a few weeks outshines even Jupiter in the SW evening sky. It rises then exactly at sunset, and will be up all night. It will be highest in the sky for best viewing about midnight, and will not be this close and bright until 2035.

The full moon, the Harvest Moon, occurs October 1st. The waning gibbous moon passes just south of bright Mars on October 3rd. The last quarter moon is October 9th, and the waning crescent moon passes just north of bright Venus on the morning of October 13th. The moon is new on October 16th. The first quarter moon makes a striking triangle with brighter Jupiter (to the west) and Saturn in the evening sky on October 22nd. The waxing gibbous moon is just west of Mars on October 28th, and below it on October 29th; see if you can Mars with your naked eye just before sunset, using the rising moon as your guide. The Full Moon (a ‘blue’ moon as the second full moon in a calendar month) is the Hunter’s moon, vert appropriate to guide the trick or treaters this Halloween!

We can not see Mercury well this month, too close to the Sun, but Venus dominates the dawn skies for the rest of the year. It passes very close to the brightest star in Leo, Regulus, on the first four days of October. Mars dominates the eastern evening sky, but Jupiter and Saturn are both still well placed for viewing in eastern Sagittarius. Remember to check out the fine triangle they make with the moon on October 22nd in the evening sky.

While the naked eye, dark adapted by several minutes away from any bright lights, is a wonderful instrument to stare up into deep space, far beyond our own Milky Way, binoculars are better for spotting specific deep sky objects. For a detailed map of northern hemisphere skies, about September 30th visit the www.skymaps.com website and download the map for October; it will have a more extensive calendar, and list of best objects for the naked eyes, binoculars, and scopes on the back of the map. Also available as the next month begins is wonderful video exploring the October sky, available from the Hubble Space Telescope website at: http://hubblesite.org/explore_astronomy/tonights_sky/.

The Big Dipper falls lower each evening. By the end of October, it will be only the three stars in the handle of Dipper still visible in the northwestern twilight. By contrast, the Little Dipper, while much fainter, is always above our northern horizon.

To the southwest, Antares and Scorpius also set soon after twilight, and will be gone by month’s end. East of the Scorpion’s tail is the teapot shape of Sagittarius, which marks the heart of our Milky Way galaxy. Saturn lies above of the pour spout now. Looking like a cloud of steam coming out of the teapot’s spout is the fine Lagoon Nebula, M-8, easily visible with the naked eye.

The brightest star of the northern hemisphere, Vega dominates the sky overhead. To the northeast of Vega is Deneb, the brightest star of Cygnus the Swan. To the south is Altair, the brightest star of Aquila the Eagle, the third member of the three bright stars that make the Summer Triangle so obvious in the NE these clear autumn evenings. To the east of Altair lies tiny Delphinus, a rare case of a constellation that does look like its namesake.

To the east, the square of Pegasus is a beacon of fall. South of it lies the only bright star of Fall, Fomalhaut. If the southern skies of Fall look sparse, it is because we are looking away from our Galaxy into the depths of intergalactic space. The constellation Cassiopeia makes a striking W, rising in the NE as the Big Dipper sets in the NW. Polaris lies about midway between them. She contains many nice star clusters for binocular users in her outer arm of our Milky Way, extending to the NE now. Her daughter, Andromeda, starts with the NE corner star of Pegasus’’ Square, and goes NE with two more bright stars in a row.

It is from the middle star, beta Andromeda, that we proceed about a quarter the way to the top star in the W of Cassiopeia, and look for a faint blur with the naked eye. M-31, the Andromeda Galaxy, is the most distant object visible with the naked eye, lying about 2.5 million light years distant. It is a bigger version of our own Galaxy, which it may collide with about three billion years from now.

Below Andromeda is her hero, Perseus. In his hand is a star most appropriate for Halloween, Algol. This star "winks" at us for six out of every 70 hours, which Arabic astronomers centuries ago found spooky, hence naming it "the ghoul". We know today it is an eclipsing binary system, with the larger, cooler orange star covering 80% of its smaller, hotter neighbor during the ‘wink’. At the foot of Perseus, the hero of "Clash of the Titans" is the fine Pleiades star cluster, the "seven sisters" that reveal hundreds of cluster members in large binoculars. This might be the best object in the sky for binocular users.

Winter will be coming soon, and in the NE we see yellow Capella rising. It is the brightest star of Auriga the Charioteer, and pair of giant stars the same temperature as our sun, but at least 100X more luminous and about 10X larger than our sun. It lies about 43 light-years distant. A little farther south, below the Pleiades, orange Aldebaran rises. It is the eye of Taurus the bull, with the V shaped Hyades star cluster around it making the head of the bull. This colorful giant star is only 2/3 as hot as our yellow sun, but 44X times larger and at 65 light years distant, one of the closest of these monster stars.