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Ephemeris: 04/27/2026 – Mare Orientale made a splash!
This is Ephemeris for Monday, April 27th. Today the Sun will be up for 14 hours and 4 minutes, setting at 8:42, and it will rise tomorrow at 6:37. The Moon, halfway from first quarter to full, will set at 5:06 tomorrow morning.
One of the pictures that the astronauts of Artemis 2 took of the far side of the moon was one that revealed chains of craters which appear to be emanating from the Sea on the edge of what we can see on the moon from the Earth, called Mare Orientale or the Eastern Sea. It was created by the impact of an asteroid onto the Moon’s surface, maybe 4 billion years ago, kicking out debris in all directions. Apparently the ejecta thrown out created chains of craters that appear to trace back to Orientale. They are most easily seen to the north and west of Orientale towards the terminator, the sunrise line, where the shadows are deeper. There’s probably chains of craters going in other directions, but they have no shadows.
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 04/14/2026 – My virtual flight with the Artemis II crew
This is Ephemeris for Tuesday, April 14th. Today the Sun will be up for 13 hours and 26 minutes, setting at 8:26, and it will rise tomorrow at 6:58. The Moon, 3 days before new, will rise at 5:55 tomorrow morning.
I hadn’t enjoyable time last week Monday afternoon listening to Artemis 2 astronauts talking with the science team on Earth about what they were seeing Moon’s far side. I have the program called Virtual Moon Atlas which allows one to see the entire Moon with the phase and shadows. And I was able to rotate it and get the phase right so it appeared pretty much as it did to the astronauts. So I was able to follow along with their discussions of the far side features that they were seeing and photographing. I could zoom in to craters and features they were talking about, but nowhere near the detail they were seeing. So I consider it to be a really great time of, in essence, flying along with the astronauts.
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EST, UT – 5 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 04/07/2026 – The Artemis II crew made amazing observations of the Moon’s Far Side
This post was made late due to some WordPress posting issues last night.
This is Ephemeris for Tuesday, April 7th. Today the Sun will be up for 13 hours and 5 minutes, setting at 8:18, and it will rise tomorrow at 7:10. The Moon, 3 days before last quarter, will rise at 2:33 tomorrow morning.
Yesterday evening the Artemis 2 crew flew over the far side of the moon. The moon to us has a waning gibbous phase. The far side is actually a waxing crescent, so most of the far side was in night. They might have gotten a good look at Mare Orientale, which is right on the edge of the moon that we see from Earth. It is a double-walled sea that looks like a bulls eye. Now they’re on their way back to the earth and will splash down in the Pacific Ocean later this week. Unlike Apollo 8 which orbited the moon, they will not be flying over any proposed landing sites. They flew over the moon’s equator while Artemis 4 will attempt to land near the moon’s South Pole. Besides, the Lunar Reconnaissance Orbiter has surveyed it much better than they could have.
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EST, UT – 5 hours) unless stated otherwise. Times will be different for other locations.
Addendum
The script for the program seen above was written and recorded Sunday night April 5th before Artemis 2’s lunar flyby. This comment is made after the flyby on the late afternoon of April 6th. I speculated about Mare Orientale being something I wanted to have them investigate. And they did spend a great deal of time observing it, so we should expect some very nice photographs of it when they’re sent back. The image above is from the Lunar Reconnaissance Orbiter taken several years ago, at least. I find it a really cool feature.
Bob Moler's Ephemeris Blog 