Sirsalis Rille

[Mike JW]

Last night there was so many candidates for sketching. In the end I went for the Sirsalis Rille. I took a different approach last night. I downloaded an image of the area to match my view and simply compared my view to the image - spotting and comparing as many feature as possible, making mental notes as I went. Doing this is so much more relaxing and in some ways I saw more rather than my customary panic at the eyepiece trying to do a rough sketch of all the features. I had a very happy hour using this approach. Today I have then sketched it from the image - cheating really but very pleasurable.

By not sketching at the eyepiece last night I was able to devote time trying to observe as many plato crate-lets as possible with the 15" Dob. A very absorbing activity. (Posted in lunar observing section as part of a bigger post)

The first sketch from a few months back was roughed out at the eyepiece, the second sketch is today's efforts based on the downloaded image.

Sirsalis Rille is 380 km long, 3km wide and 230m deep.It is strange in that is so straight. Possibly a collapsed lava tube that fed lava to Ocean Procellarum. However, it could be land that has slipped between two faults (a graben). I am fascinated by the way it cuts through the highlands. There are magnetic anomalies associated with the rille. Orbital photos show it bending through craters.

 

 

[Fraunhoffer]

That looks a very interesting area. I will have to look that up. Lovely sketches. It was quite cold sketching at the eyepiece yesterday.

 

[Fraunhoffer]

Finally, I managed to see it last night on day 12 of current lunar. I needed to go to 240x to see it. Thanks for the tip. 

 

 

[Stu]

Very nice sketch. I saw it last night with my Tak Mewlon, very clear feature and lovely at high power.

[Mike JW]

Stu and Fraunhoffer - glad you found it and well worth a visit. Mike