Last month, the full moon took the liberty of scanning Mars from the sky for up to an hour or more from some locations. Perhaps you were lucky enough to have clear skies to witness the action. At the time, I thought Mars might be bright enough to follow all the way to the edge of the Moon without optical aid. I was wrong. At least my eyes weren’t up to the task. Through binoculars and telescopes it was amazing.
The difference in size between the two objects, as well as the contrast of colors, made for a delightful and informative spectacle. Watching the planet “rise” from behind the moon as it returned to view was the highlight.
Contributed / Stellarium
This time, observers across much of the United States will see the grainy moon pass close to Mars in conjunction on Monday night, January 30th. Although they will be close to each other all night, they will have to zip close to Mars around 12:30. AM (Jan. 31) for the East Coast; 11:30 p.m. CT; 10:30 p.m. for the mountain states and 9-9:30 p.m. for the West Coast. For American and Canadian observers, the Moon will slide below (south) Mars.
Here’s a sample of cities and approximate local times for when the moon and planet are closest. separation in arc minute. For reference, the diameter of the full moon is 1/2° or 30 arcminutes. For convenience, we use the initial symbol (′) as an abbreviation for arc minutes. If the distance between Mars and the Moon is 10′, that is one-third the diameter of the full Moon—a narrow interval when viewed with the naked eye.
Duluth, Minnesota – 11:30 p.m., 11′
Minneapolis – 11:30 p.m. 9′
Fargo – 11:30 p.m., 10′
Chicago – 11:48 pm, 8′
Philadelphia – 12:50 a.m. (January 31), 9 p.m
Memphis – 11:48 p.m., 1 (visible in binoculars/telescope)
Denver – 10:25 p.m., 3
Seattle – 9:05 p.m., 11 a.m
Geoff Hitchcox Contributed / 2023 Google Maps Track made with Occult software
If you are reading this and live South From the double green line shown in the map, the Moon will completely cover (fuzzy) Mars. This includes the cities of Montgomery, Oklahoma City, Albuquerque, Las Vegas, Los Angeles, and part of Hawaii. An interactive version of the map is available at poyntsource.com/New/Google/Mars_2023_Jan_31.htm.
Contributed / Stellarium
The planet will disappear at the dark edge at night of the Moon and return to view along the bright, sunlit side. Go to lunar-occultations.com/iota/planets/0131mars.htm for a list of cities and their disappearance and reappearance times. Note that times displayed are in UT or Coordinated Universal Time. subtract 5 hours for EST; 6 hours for CST; 7 hours for MST and 8 hours for PST.
How close can you follow Mars to the edge of the moon with just your eyes? Good question! It depends on sky conditions and how good you are at hunting outside a point of moonlight. Mars has faded a bit since its last disappearance. In early December, it shone at -1.9 magnitude (brighter than Sirius). This time it is more dim by magnitude at -0.3.
Contributed / Stellarium
I think observers who live where the planet passes 10′ or less from the Moon will temporarily miss it with the naked eye. Binoculars and small telescopes should show that Mars up to the edge of the moon is no problem.
No matter what, we’re all going to see a really sweet connection.