For October 2024, the moon is new on October 2nd. The waxing crescent makes a nice pairing with bright Venus in twilight on October 5th. The first quarter moon is on October 10th. The waxing gibbous moon is just west of Saturn on the evening of October 13th, and to the left of it the following evening. The Hunter’s Full Moon on October 17th is also a "supermoon", the closest full moon of 2024. In the morning sky, the waning gibbous moon passes north of bright Jupiter on October 21st. The last quarter moon is just below reddish Mars on October 24th in the dawn. No moon this Halloween, alas; it will be new on November 1st.
Mercury lies too close to the Sun for visibility from Earth this month. Venus pulls away from the Sun, higher in the southwestern sky, and passes just above Antares on October 25th. It appears gibbous in the telescope, still on the far side of the Sun. Mars is in the dawn sky in Gemini, and is also now gibbous in the scope. It passes south of the Twins, Castor and Pollux, with the moon joining the group on October 23rd. Jupiter reaches opposition in early November, and rises about 10 PM in the northeast in Taurus at midmonth. But Saturn is well up in the SE at sunset in Aquarius. Its rings are very thin and closing, become edge on at its equinox in May 2025, almost invisible from earth.
While T Corona borealis has still not flared as expected at this writing, we do hope it will soon. Its position on the comet finder chart, between the crown and Hercules overhead, is noted. Ideally it will flare when the comet is at its best! The big question is just how bright Comet Tsuchinshan-ATLAS 2023 A3 will be in the evening skies this month. So far, it has stayed intact and brightened more than predicted, and will get closest to the Sun at the end of September. When it passes between us and the Sun in mid October, it may become the best naked eye comet for most of us living now. Stay tuned!
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. Here is the little bear in the woods at Big Lagoon at our August Gaze. The app is called "Nocturne" and it is free for iPhones and ideal for shooting the comet in October. Note you can add the constellations and labels to the original, a great way to teach kids the constellations
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. If it lives up to expectations, the comet will move up and to the east each evening through Ophiuchus above them this 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 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. 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 2.5 million light years distant. South of M31 is the other great spiral in our Local Group of Galaxies. M-33 in Triangulum is seen from a higher viewing angle, so the spiral arms are even more striking. It too is about three million light years distant Both are visible in good binocs.
Below the head of Pegasus is Aquarius, the Water Carrier, now home to Saturn. Below his western foot is the only bright star of the southern fall sky, Fomalhaut. It means the "mouth of the fish", and carries on the watery grouping of Pisces the Fish (home to Jupiter now), Capricornus the sea goat (with Saturn in its tail), Cetus the Whale in the SE, and Grus the Crane due south 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, an orange giant covering most of its blue companion.
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. The giant planet Jupiter now sits just west of this famous group in early evenings.
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. Again, binoculars come in handy to reveal three fine Messier open clusters, M-36, M-37, and M-38, all within the pentagon of Auriga.
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. Jupiter is now near the lower horn of the bull.
