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Ephemeris: 09/12/2024 – Does the Moon have a square crater?
This is Ephemeris for Thursday, September 12th. Today the Sun will be up for 12 hours and 39 minutes, setting at 7:58, and it will rise tomorrow at 7:19. The Moon, 1 day past first quarter, will set at 1:11 tomorrow morning.
I built my first telescope in the mid 1950s from the kit. It had a 5-inch diameter mirror. Of course one of the first things I looked at was the Moon. And while familiarizing myself with the Moon’s features I noticed that around first quarter moon there was a funny little crater near the Moon’s North Pole that looked square. All the other craters were round. This one being near the North Pole was foreshortened a bit, so it’ll look rectangular. It sure had walls that looked like they were straight rather than curved. The crater’s name is Barrow. And the description I found of it said it had an interesting shape, though they didn’t mention it was square. Looking closely at it, it is squarish but in small telescopes it definitely looks like it’s a square crater. The best time to try to spot it is around first quarter moon or up to a couple of days later.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
The base imagery used for the Virtual Moon Atlas, I believe, came from the Clementine spacecraft, a joint project of NASA and the Department of Defense, which orbited the Moon for 71 days in the mid 90s and then was sent out to an asteroid. However, on the way to the asteroid a problem occurred and Clementine was “lost and gone forever”.
05/06/2014 – Ephemeris – A square crater on the moon
Ephemeris for Tuesday, May 6th. The sun rises at 6:25. It’ll be up for 14 hours and 27 minutes, setting at 8:53. The moon, at first quarter today, will set at 2:40 tomorrow morning.
Tonight’s moon reveals some great features. Back in my early astronomy days, one of the odd thing I saw on the moon with my telescope at about this phase, was what appeared as a square crater on the moon. Craters are supposed to be round. This one was near the north pole of the moon. It can be seen with a small telescope. It was given the name Barrow. I’ve since confirmed that it is indeed quite square, with a small crater, Barrow A sitting on one corner. The Lunar Reconnaissance Orbiter shows this in great detail. Also on the north end of the moon tonight is the Alpine Valley, which looks like a gash crossing the Lunar Alps. Lunar mountain ranges tend to be named for earthly mountains, but are really crater walls.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
First quarter Moon at 10 p.m. May 6, 2014. Created using Virtual Moon Atlas.
The square crater Barrow and the Alpine Valley as it would be seen in a telescope on May 6, 2014 at 10 p.m. Created using Virtual Moon Atlas.
The Barrow crater as imaged by the Lunar Reconnaissance Orbiter. Credit NASA/GSFC/Arizona State University, Virtual Moon Atlas.
Actually Barrow almost looks pentagonal in the above image.
The Alpine Valley as imaged by the Lunar Reconnaissance Orbiter. Credit NASA/GSFC/Arizona State University, Virtual Moon Atlas.
Bob Moler's Ephemeris Blog 