Tuesday 15 April 2008

A brief daylight moon - 14th April

I got out for about 45 minutes last night at about 7 pm with my youngest to take a look at the moon. After leveling, so much easier in daylight, I went to align the scope on the moon. This ought to be easy, but the RDF is about as much use as a chocolate fireguard during the day, and sighting by eye along the tube just doesn't work. In the end, after a rough along the tube align, I just took out the ep, and looked in the diagonal until the disk showed in the mirror, then popped the ep back in and used Solar System align to set the mount. This worked well and I'll use this again for daylight lunar observing.

I lined up the scope so that Montes Apenninus and Montes Caucsus were in view and pointed them out. Then pointed out Plato and Erosthenes. This was a little tricky as the mount was set for me sitting on a chair, and the ep was at just the wrong height, so with a little twist of the locking screw, I rotated the diagonal around so the ep was at about 45° and he could see in fine. He saw these things, but decided he'd rather look through bins, so I stopped viewing for a few minutes to go grab a tripod, bins and the adapter. Then set him up so he could look at the moon through them.

Once done, I went back to the scope, reset it for me and had a brief observing session. I started at the obvious feature being the mountains of the Apennines and Caucasus. I grabbed Plato and Erosthenes which anchor either end and made a rough sketch. I need to get better at drawing these things, at the moment they are pen and ink on lined paper that gives me a rough reference for using VMA to identify what I've seen using the Moon Atlas as a guide to the referent points. If I can improve I'm sure I can get some decent records and probably learn the features better. Something for another day, and I mean day, sketching at night is a real challenge.

Hmm, where was I. Ah yes, in between the arms of the mountains, I found the crater Archimedes. This I used in the sketch, with Erosthenes and Plato as the referent points. The sketch found me Aristillus, Autolycus, Bancroft, Theaetetus, Cassini and Wallace. I also spotted some mountain peaks near Plato, they looked like small Pyramids, and I think I saw Mons Piton and Mons Pico along with Montes Tenerife (not sure I'd want to go on holiday to this Tenerife though, maybe a little cold).

Moving on along the terminator, I then say Timocharis, Mosting, Lalande, Thebit and Tycho. I tried to see Fra Mauro, but this was hiding in shadow. I also had a look at Clavius. Whilst Clavius was still partly in the terminator, the main outer crater was visible and the rim of each interior crater was lit. Quite a spectacular way to see Clavius and I wish I had some way to capture this view. Ah well.

At this point, the moon was quickly covered in clouds, I was going to watch and see what happened as patchy clouds had been passing all day, but then I felt the first drops of rain. I quickly lowered the scope to a parked position (horizontal) it doesn't do any faster than quick (9x slew), unplugged everything, and moved it all indoors to avoid it getting overly wet. I kept checking throughout the evening, but whilst there were gaps and cloud banks, there never looked to be enough gap, so I didn't get out again. This is the drawback of the NexStar over the camera tripod. As it takes a few minutes to setup and align to get the tracking, if I only have a 10 minute or so window of opportunity, I don't setup anymore. The camera tripod would be up and running as soon as it was outside. I'd rather have the tracking though any day of the year.

After we'd come inside, my youngest drew a sketch of the moon as he saw it, I'll try and scan it later.

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