Reiner Gamma, a lunar swirl

[Nik271]

This morning I had a quick look at the Moon and learned something interesting. 

I was using too much power (just forgot the eyepiece from the previous observation of Mars) So 180 Skymax at x300 -the Moon was wavering with the morning turbulence but still the features near the terminator were clear and contrasty. I love the Mak.

First I observed the Schroteri valley: close to the terminator presenting a good view with its zig-zaggin shape near Aristarchus and Herodotus crates, one of my favourite areas of the Moon.

Next I looked at Marius, trying to spot the Marius 'hills' and as the scenery drifted west I noticed a oval bright patch to the southwest of Marius. It was quite bright and had a 'wavy' boundary.

I made a note to check it up. Thankfully there is the free online LROC map: https://quickmap.lroc.asu.edu/ which has all kinds of information overlays.

It turned out this oval is called Reiner Gamma. Its not a crater but a 'lunar swirl'. Wikipedia has a nice article on these: https://en.wikipedia.org/wiki/Lunar_swirls

You definitely don't need x300 to see it, just about any telescope will show it, probably even at x50.

Apparently their bright albedo is due to magnetic anomalies which bend the solar wind away so the rock is not as weathered and stays 'young'.

The source of the anomalies is still a mystery. Interesting stuff! I hope we go back there and investigate some day soon.

Clear skies!

 

Nikolay

 

 

[Kyle Allen]

Interesting, thanks. I’ll have to look out for this next time it’s visible. 😀