October skies of the Gulf Coast
For October 2021, the crescent moon wanes in the dawn until the new moon on October 6. It makes a striking pairing with brilliant Venus in the dusk on the weekend of October 8-9. The star close to Venus is delta Scorpii, the north claw of Scorpius. Note the earthshine for a nice photo with even your smartphones. The moon is first quarter on October 12, and just south of Saturn on the next evening. It passes below bright Jupiter on October 14-15. The full moon for October, the Hunter’s Moon, is on October 20, so alas, no moon for the pumpkin patch this Halloween! In fact, the last quarter moon will rise about midnight on the 28 and will be a waning crescent in the dawn on Halloween morn.
We can’t see Mercury well this month, being too close to the Sun, but Venus dominates the evening skies for the rest of 2021. It passes 1.4 degrees north of Antares in Scorpius on October 14 and moves into Sagittarius by month’s end. Telescopically it is a bright waning gibbous disk, with no details in its cloud deck, alas. Mars, like Mercury, lies too close to the Sun now. But Jupiter and Saturn are still well placed for fall sky observers. They lie at opposite ends of Capricornus, in the southeast.
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. Visit skymaps.com for a more extensive calendar, and a list of best objects for the naked eyes, binoculars, and scopes on the back of the map.
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 here along the Gulf Coast.
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 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 northeast 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 south, Saturn is in the head of Capricornus, and Jupiter is above its tail. Aquarius and Pisces are among the faintest of the zodiacal constellations and need dark skies to pick out. Fomalhaut is the only first-magnitude star of the southeast fall sky and stands alone above the southeast horizon now.
To the east, the square of Pegasus is a beacon of fall. If the southern skies of fall look sparse, it is because we are looking away from our Galaxy into the depths of intergalactic space. 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 northeast now. Her daughter, Andromeda, starts with the northeast corner star of Pegasus’ square and goes northeast 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. The Andromeda Galaxy, is the most distant object visible to 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 northeast 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 100 times more luminous and about 10 times 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 44 times larger and at 65 light-years distant, one of the closest of these monster stars.
The EAAA has one last public gaze at the Pensacola Beach Pavilion. We will set up on the weekends of the first quarter moon for fine views of the moon, planets, bright satellites. We will hand out free star charts, show off a variety of telescopes in all sizes and price ranges, help you learn to use your own new scope or binoculars or smartphone for astrophotography, and teach you the brighter constellations with our green laser pointers. With clear skies permitting, we plan to be south of the famed Beach Ball Water Tower on October 15-16.
For more information on the Escambia Amateur Astronomers, visit www.eaaa.net, join us on Facebook, or call our sponsor, Lauren Rogers at Pensacola State College at (850) 484-1155, or e-mail her at firstname.lastname@example.org. All EAAA events are free and open to the public.