Good evening, all lunar enthusiasts! I had a small opportunity to observe the half Moon last Tuesday night for about half an hour.
At a mere 11X in the guidescope, I could make out with no difficulty Rupes Recta quite close to the terminator in Mare Nubium. It is 110 kilometres long. But it was truly spectacular in the main scope at just 40X. To its west I could see Birt and Birt A. I then increased to 112X, and wondered would I see a very slim rille which is only 50 kilometres long called Rima Birt.
I went up to 140X and 167X, and lo and behold there it was! It is parallel to Rupes Recta and is west of the crater Birt. At the northern edge of Rima Birt is a tiny crater called Birt E, and I could see this little fellow first before spotting the rille.
I have had the new and the old versions of Antonin Rukl's book Atlas of the Moon over many years. If anyone turns up Map 54 in either book, you can see Rima Birt very clearly marked out in both. I have tried many times to observe Rima Birt over the last 20 years, and failed miserably every time I attempted to find it. Now I am just simply thrilled to be able to tick him off in my lunar atlases.
Has anyone else seen it in the past? Or even just last night?
Thank you for reading.
Aubrey.
  