Sunday, February 29, 2004


Enough with heavy topics today. I mentioned that I had purchased a Photon Instruments 5" refractor, and after a little bit of struggle, I am reasonably pleased with its optical performance. I also purchased a Losmandy GM-8 mount recently, used, for about $600 less than new. I was reluctant to buy Chinese for fear of putting money into the hands of a kleptocratic government that I consider the most likely future direct war threat to the U.S., but I was also a little wary because the Chinese factory quality control leaves a lot to be desired. I am so glad that I spent a bit more to get a used Losmandy. You can't see it in the pictures, but it is a real quality piece of work.

Here's a couple of pictures of the scope on the mount:

Now, the mount didn't come with what is called a dovetail plate. This mounts to the bottom of the telescope, and lets you slide the telescope in and out of the saddle quickly. I ordered up a dovetail plate ($75 from Woodland Hills Camera), but since the sky was gloriously clear Saturday, I decided that I couldn't wait, and I made an interim dovetail plate out of red oak, which you can see here:

It's actually pretty simple; I started with a 1/2" piece of red oak, then set the table saw to a 45 degree angle. I trimmed in down both sides to the required width. Then I kept trimming, until it actually fit into the dovetail. Then I drilled and tapped metric M6 holes into it, and screwed the mounting rings into the dovetail. It's not beautiful (the real part is black anodized aluminum), and I expect that it won't last forever, but it works for a few days. I can use drill some more holes and use it to mount any other telescopes or odds and ends.

Here's a detailed picture of the Losmandy GM-8 head:

I can't give a detailed description right now, but I called my son out to show off one of the nice features--that I can use the four button hand controller to pan slowly across the Moon's surface. (I've been using ancient mount technology until recently; I'm surprised that there isn't a steam engine in the mount that I use for the reflector.) He thought that was cool, but he was also really impressed how sharp to the Photon Instruments refractor is.

I will be doing some astrophotography soon. Alas, just as I was getting set up, my daughter called to talk about wedding plans, and as such conversations go, by the time I was back outside, the little motorcycle battery I have been using to power the mount had gone dead. By the time I finished recharging it, frost had formed on the front lens.

The incident Saturday night where I tripped over the power card, breaking the plug--well, not quite as catastrophic as the scene where Gilligan trips over the space probe, dooming the castaways to several more seasons on Gilligan's Island, but frustrating, nonetheless.

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