In this episode of What's in the Sky this Month, Teagan reviews some of the beautiful celestial objects you can see in the month of January!
Image credit: NASA
Mars at Opposition & Occulted
Unlike Jupiter and Saturn, Mars only reaches opposition once every two years or so, with the last opposition occurring in December 2022. At that time, the planet could be found in Taurus and shone at magnitude -1.9. This year, opposition occurs on January 15th in Gemini, close to the bright stars Castor and Pollux. At magnitude -1.4, it’s a little dimmer than before but will still appear as a brilliant, coppery “star” in the evening sky and a must-see target for telescopic observers.
Be sure to step outside on the 13th, when you’ll have the rare opportunity to see the Moon pass in front of the planet (or occult it). The exact circumstances will vary, depending on your location, but those on the East Coast can expect to see Mars disappear between 9:00 PM and 9:30 PM, while those on the West Coast will witness the event between 5:45 PM and 6:30 PM. Again, depending on your location, the planet will then reappear between 35 minutes and a little more than an hour later.
OUR NEAREST NEIGHBORS
The evening twilight sky continues to be dominated by Venus, which reaches greatest elongation from the Sun on the 9th. Just a little to the upper left is Saturn. A crescent Moon appears to the left of Venus on the 3rd and then to the upper left of the ringed planet the following night. The two planets are moving closer together in the sky and will be closest on the 18th, when 2.2 degrees will separate them. Saturn is then revisited by the crescent Moon on the 31st. Neptune remains visible for a short time in the evening during the first half of the month, while Uranus, still close to the Pleiades in Taurus, is well-placed for observation throughout much of the night. A little further east, and also in Taurus, Jupiter can be found within the same 10x50 binocular field of view as the bright star Aldebaran, with a waxing gibbous Moon close by on the 10th. However, January really belongs to Mars, which reaches opposition this month. This leaves Mercury alone in the predawn twilight; look for it from about 30 minutes before sunrise, low over the southeastern horizon, during the first half of the month. Lastly, there’s a full Wolf Moon on the 13th, and then the Moon turns new on the 29th.
Image credit: Jim Mazur
Messier 37 - The Gold Dust Cluster
One of three Messier open star clusters in Auriga, Messier 37 can be spotted within the same 10x50 binocular field of view as Theta Aurigae. A telescope at a low magnification of around 30x will show a large splash of stars, with a slightly brighter yellow-orange star near the center.
Image credit: Scott Rak
NGC 2169 - The 37 Cluster
Starting from Betelgeuse in Orion, star hop to Mu Orionis, and then to the close pair of 73 and 74 Orionis. About two degrees northwest of this pair is NGC 2169, a tiny group of stars that looks like the number 37 at low power through a telescope.
Image credit: Aquil Virgos
Gamma Leporis
Another winter double, Gamma Leporis, can be found nearly thirteen degrees due south of Rigel. This is a pretty pair, easily split at around 35x, that shows a creamy primary star that’s about twice as bright as its coppery companion.
Image credit: NASA
Messier 42 - The Great Orion Nebula
It’s almost impossible to step outside on a winter’s night and not devote some time to the Great Orion Nebula. To the naked eye, it appears as only a misty patch, but almost any telescope will show a textured, greenish, smoky cloud with four tiny, brilliant stars - the Trapezium - at its center.
STELLAR CONCEPTS
Opposition: An object is said to be at opposition when it appears directly opposite the Sun in the sky. This being the case, it will rise at sunset, be due south at midnight (or 1 AM if your area is observing daylight savings time), and will then set at sunrise, making it visible throughout the entire night. The term almost always applies to a planet (specifically, the outer planets Mars, Jupiter, Saturn, Uranus, and Neptune) but can also be applied to deep sky objects, such as star clusters, nebulae, or galaxies.
