Good morning all!
It is quite a rarity for me to be able to observe the waning gibbous Moon due to having to be awake at odd hours to do so, however, being a weekend day and not having to work the next day (yay!) made it possible to observe the Moon and Mars earlier this morning. The pair was quite striking, separated only by less than a degree! I spent some time observing Mars but was struggling a bit making out the delicate details with the poor transparency we had from rain earlier in the night. At about 6:30 UTC I moved on to the Moon. There was a feature in eastern Mare Serenitatis that instantly caught my eye. The thin, winding lunar ridges span from nearly Plinius to Posidonius, >300 km, and appeared almost 3D-like due to the close approach of the Terminator and the Sun beginning to set for this feature/casting shadows to add depth. In the eyepiece, this feature reminded me of a sea serpent winding its' way through the water. I gave the feature a nickname "The Sea Snake of Serenity" as that is what it reminds me of so much.
This morning I reviewed my Rukl Atlas of the Moon to properly identify the feature. On map No. 24, I learned that my sea snake is actually comprised of two features, Dorsa Lister (runs North from Plinius to about half the length of the feature), and Dorsa Smirnov (the Northern half). Dorsa I have learned means system of wrinkle ridges, and Dorsum is a wrinkle ridge. I am still a novice lunar observer, but have added these two types of features to my geographical lunar toolbox so to speak.
Part of what makes lunar observing so fun for me is the constantly changing appearances of all the features due to the shadow details. I attached a photo of the feature through my eyepiece at 350X along with a photo of map No 24 from my Rukl atlas for you to see.
Have you seen this feature before in similar conditions? What were your thoughts?
Are there any other Dorsa that impress you? If so, I would like to hear your recommendations on which ones I should check out next!
Clear, steady skies,