Friday, 15 February 2008

Sunning myself in moonlight

After my short lunchtime excursion, I got outside again after work for about 20 minutes with my Lunar 100 challenge and picked off three or four more. This was actually easier during the day as the little numbers in the chart are printed in red which is a total disaster with a red torch...

Then back inside for some food, hmm, a nice toasty hot lasagne... I digress.

After food, I popped back outside again with the Mother in Law to show her a few of the heavenly sights through the scope. Not so easy as the Moon is bright, and even the sisters are looking decidedly pale and uninteresting. However, we had a good look at the moon, and I admitted that I had no idea what all those craters were called. I also don't think my paper lunar map thingy that came with my scope is gonna be up to much at night, far to dark and yet really glossy at the same time. Anyho, I swung the scope across a couple of other sights. M42, hard to see tonight, but hints are there, around to look at the Horse and Rider in Ursa Major, and back to finish on the unusually pale sisters.

Then back inside for sometime, as it was time for MiL to head home. Some time passed, about 1.5 hours in all and I was able to get back out at 2120 for a good long look at the moon. There are a few very obvious and large objects that leapt out at me first. Copernicus and the Apenines being the obvious. One of my objectives for tonight was to find the straight wall or Rupus Rectus, and tick off a few more items on the Lunar 100. I'd seen an image posted on a forum of the straight wall and felt inspired to locate it. That was the first challenge. It took me a while popping back and forwards from NW, a map that came with my scope and the Lunar 100 chart to the computer for VMA to narrow the position down. This was made all the harder by the peculiarities induced by the objective lens and diagonal mirror, inherent in any refractor. After some time, I'd managed to figure out the approximate location and using the 5mm Ortho lens (80x) I pointed the scope at the correct area. I looked and looked again, but there was no sign of the wall. Odd, thought I. So I watched, I moved the scope back, I watched some more. Moved the scope again (damn the moon moved quickly at 80x). Suddenly, as if the wall had been hiding from more, or just been built, this line leapt up at me from out of the crater/sea floor and nearly gave me a black eye. WOW!.

Then I was off. I'd got me a reference point on La Lune's surface and from there I was able to go on and find a number of other items. I next picked up a couple of larger objects that I hadn't noted before, Erastenes, Plato and Archimes. Then I spotted an odd effect. It took me a little while to work out what it was that had caught my eye. Just beyond the terminator I could see all these little bright specks. Was this a trick of my eye, some odd reflections in the scope from the brightness of La Lune ? No. None of these. I got there in the end, the cold must have been addling my thought processes. It was the sun shining on the high points of the lunar surface just behind the terminator shadow. A pretty spectacle, and something I wasn't expecting to see.

After working this one out, I went on to take a look at Tycho, another reference point, get a few of these and finding the objects in the 100 become easier. I spotted the Alphonsus dark spots, onto the Davy crater chain which were quite a toughy but I think I got them. I've marked them up anyway. Ptolemeus B (this was a tiny little spot, but it was there). I then started looking for a couple of real toughies and wasn't having a lot of luck. So then I dropped in the barlow. This took my up to 160x and the movement rate of the moon become almost unusable. Any crater shot through the FOV in less than 30 seconds, and bringing the scope back to target on quite a stiff photo tripod was quite tough. But it was worth it. I think I bagged the Gylden Valley and Mosting A. I then took the barlow out as it was to hard to keep the area of the moon I was looking at in view. Gotta sort out my mount soon.

Back to 80x and found Hipparchus, then onto the Regiomontanus central peak. I tried to find some rills, but either I was beginning to shiver too much and couldn't focus properly, it was darn cold last night, and I'd messed up my layering, or wasn't patient enough I don't know. So anyway, I moved on. I found the Altai Scarp, this did the same thing as the wall, and after hunting for some time, just appeared as if by magic. From there Thophils, Cyrillus and Catharina were easy, Fracactorius was also nearby. Then onto Clavius. I then went back to the wall and found Pitatus and Hesiodus A.

At this point, 90 minutes after emergin, the shivers were getting to much, and I decided to go have a quick look at Saturn (the usual superb views, although I was shivering a bit much to see any moons). A quick look at a washed out Beehive, still a pleasing view, but just so much less detail. And in to try and warm up by getting me around a hot cup of tea.

This is the first time I've been able to pop back in the house to look at things like VMA on the computer without mucking up my observing. It was also the first time I've viewed using a white light torch, and for the moon, which is such a bright target, it actually worked quite well. The white light helped me with the Lunar 100 red numbering that just can't be seen with a red torch.
I now have just over 20% of the Lunar 100 marked up. (22 to be exact) and really enjoyed the experience. It was very different to the normal cluster gazing, in one respect, but showed me that just watching one spot for some time can reveal all sorts of wonders, although I didn't realise a wall could be built in a fraction of a second. I'm not sure whether more can be added to the 100 tonight, it will depend on how much further the terminator will have moved, but I'm certainly going to give it a try, and will also wrap up a lot more warmly. One note to self, write more neatly so you can work out what you've written. Ok, so it's tough wearing gloves and shivering like that, but it's important.

I'd like to say thanks to Phil for his Straight Wall image and Ian for his sketch which helped me with orientation.