Drawing of the crater Atlas on the Moon (3rd January 2025)

After I had completed my phase observation of Venus on the 3rd, I thought I would have a go at drawing some feature on the nearby Moon. The Moon at this stage was only 4 days old and a nice thin crescent. Near the terminator were a number of nicely lit craters and I settled on this one to draw:-

Atlas is an 89 km diameter impact crater that can be found at latitude 47 degrees North and longitude 44 degrees East (lunar coordinates). I was using my Celestron NexStar 102 SLT with a 9mm orthoscopic eyepiece and a star diagonal. This gave a magnification of 73x. I started observing at 16:25 UT and finished at 16:48. The seeing was pretty good and AII on the Antoniadi scale.

The first thing to point out was that I didn't know I was drawing Atlas before I started. I had to work this out after I had finished (I did draw the positions of craters Franklin and Cepheus as a guide to recognition). What amazed me was my lack of understanding of the orientation of what I was looking at! Fortunately, I have a very good Atlas (the Collins Atlas of the Night Sky by Storm Dunlop) which has lunar maps for each type of telescope combination. So with a refractor with a star diagonal in the position I had it in, lunar West and East were in the right position but North and South were flipped (see my diagram). This was a surprise to me and, as I had been using the same set-up for my Venus observations, it meant that I had been assuming North and South were the wrong way round (not so easy to tell this for a featureless surface like Venus). Ho hum, as they say. Rookie error! So if you want to view my drawing in the usual manner you would have to reflect in a line along the east-west axis.

Note also another very confusing thing that I didn't appreciate. When you look at the moon directly what is labelled as the East side of the Moon is not on the east side of the sky - it is on the west! It was decided to have this type of labelling because then the terminator moves from lunar East to West, a bit like on Earth. Very confusing if you are trying to orientate yourself.

Anyway, I was able to identify that it was Atlas that I had been drawing. Note that Atlas was just beyond the terminator and in the illuminated part of the Moon. West of Atlas the Moon was in shadow. You can see there is quite a dark wall on the North side of the crater and this because there is another crater next to it (Atlas E) which causes this feature (have a look at this Sky at Night article and the image of this area). I think another smaller crater (Atlas A) is to the South.

My drawing may look a bit small but in my defense I would say that drawing at the telescope in freezing conditions is not easy! This is the first time I had tried this in a serious way and it was quite taxing to try and get the details right.

All text and images © Duncan Hale-Sutton 2025