For October 2019, the waxing crescent moon passes bright Jupiter on October 3. It is first quarter on October 5, to the lower right of Saturn. Full moon, the Hunter’s Moon, is October 13. Last quarter is October 20. New Moon is October 27, which means that by Halloween, the waxing crescent moon will again be close to Jupiter right after sunset for a telescopic treat for the neighborhood kids, so get out the telescope and the Milky Way bars.
We can see the two inner planets, Mercury and Venus, low in the SW about 40 minutes after sunset on October 22. Venus will be to the right and much brighter — get a site that has a flat southwest horizon to spot them. Mercury soon passes between us and the Sun on November 11, a transit that will be visible from here — more on it next month! Venus continues to pull away from the Sun for the rest of 2019, getting higher and brighter in the western evening sky each night. Mars returns to the dawn sky just before sunrise by months end. Jupiter and Saturn are both well-placed for observation in the southwest evening sky this month, but look for Venus to overtake Jupiter in the twilight in November.
Jupiter in Ophiuchus will get lost also getting lost in the sun’s glare by Thanksgiving, Saturn is still out in Sagittarius in the southwest, but also will be gone by Christmas, leaving Venus the only evening planet by New Years. 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, visit the Skymaps website.
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 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. This stellar nursery is ablaze with new stars and steamers of gas and dust blown about in their energetic births. In the same binocular field just north of the Lagoon is M-20, the Trifid Nebula. Many other clusters visible in binoculars as you sweep northward along the Milky Way, and are plotted on the sky map for the month.
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 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 northeast as the Big Dipper sets in the northwest. 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. 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 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 two-thirds 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 Escambia Amateur Astronomers Sidewalk Gazing: 6 p.m. Oct. 4 and 5, Gulfside Performance Pavilion, Pensacola Beach.
Public Gaze at Big Lagoon State Park: Sunset, Oct. 19. Free, but park admission required.
For more information, join the Escambia Amateur Astronomers group on Facebook., or visit their website at eaaa.net, or contact sponsor Lauren Rogers at (850) 484-1155 or by email at email@example.com.
Dr. John Wayne Wooten has been teaching science since 1970, with a special concentration on astronomy. He received his Doctor of Education in Astronomy from University of Florida in 1979. He was an educator at Pensacola State College since 1974 and University of West Florida since 1984 before retiring in 2017. He still continues to teach distance learning astronomy for Tennessee colleges. He and his wife, Merry, have been married since 1980 and they have two sons, Michael and Trevor.