Pac-Man Moon & A Serpent

[The Wave Catcher]

I’ve had many observations since my last astronomy posts but I thought I’d share my last Sunday’s simple city observations before a work day.

2023-12-17
17:40-19:20 CST

The 30% waxing crescent Moon was high in the twilight sky. The weather was nice again very calm, clear, and 64° F and falling. I brought my usual AT80ED out to check it out. Seeing was about 8/10.

The most striking feature was the crater Theophilus and its two central peaks. Mons Argaeus looked humongous just inside the day lit side of the terminator.



At 00:07:45 UTC (12/18/2023), I’m pretty sure I observed an impact on the dark side of the moon, west of Theophilus by maybe 100 km! It may have just been a glitch in eye/brain circuit but I documented it just in case.

I noticed a nearby star just to the east of the Moon and found it was HIP 110518 and that it was going to be eclipsed by the Moon at about 0045 UTC according to Stellarium. In a wide angle view it looked as if a giant PacMan was about to devour a star.

Saturn was only a few degrees from the Moon so I took a cursory look at it with my 4 mm (140x) eyepiece. I could see the usual features, though Saturn seemed slightly smaller than my recent observations as expected as we move away from it. The rings are getting more edge on every time I look at them but the Cassini Gap is still discernible. Titan was easy to see and I could see Rhea with averted vision. The North Equatorial Belt (NEB) was visible.

I went back to the Moon to see the occultation. I watched HIP 110518 blink out at 00:43:11 UTC (2023-12-18)! It always amazes me to actually see the Moon move relative to background stars. The dark side of the Moon was bright enough to see craters due to earthshine. I could especially see one bright crater in the northwestern limb near the vicinity of Strabo Crater. Interestingly, I couldn’t find any bright craters in the region that stand out during sunlit periods.

Another cool feature that was becoming more visible as I watched was a giant serpentine ridge called Dorsa Smirnov. Normally, it just looks like a slight ripple in the smooth surface of the “Sea of Serenity”. Below is my iPhone capture of it.



It was now supper time and 58° so I quit for the night since I had to go to work in the morning.

[messier 111]

very nice photos, and a very interesting report, thx.

[John Baars]

Very interesting feature, this Dorsa Smirnov.
Nice report, thanks!

[helicon]

Nice report Steve, thanks for sharing it. Sharp eyed observing and impressive to catch the features you enumerated as well as the occultation. Congrats on the winning the VROD for today!

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[The Wave Catcher]

Nice report Steve, thanks for sharing it. Sharp eyed observing and impressive to catch the features you enumerated as well as the occultation. Congrats on the winning the VROD for today!

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Awesome, thank you!

[John Baars]

Congratulations on the VROD!

[kt4hx]

Nice report and images Steve. While I am more galaxy oriented in my observing and not so much of a "lunar-tic", I really like the crater Theophilus. I observed it with my grandson last month. Seemingly appropriate, his name is Theo! Congrats on the well deserved VROD.

[Bigzmey]

Thanks for the enjoyable report Steve and congrats on the VROD!