Astro Blogs

poor mans' autoguider

so, while waiting out this interminable cloudy/rainy weather (not one clear night since March 9th?!?), I started hacking on a homebrew autoguider.

I acquired a celestron 9x50 straight through finderscope in trade for an old eyepiece I don't use, and I scored a 'golf ball' logitech webcam, which I promptly gutted after determining that it functioned, reducing it to a little 1.5 x 1 inch PCBA with the camera chip on one side, and the USB cable on the other side.

is it a hobby or a drug?

Astrophotography... I resisted the lure of this for years, knowing I'd be sucked into a spiral of spending money on toys :)

Further adventures with a C80-SP

Last episode, I got my hands on this lovely old Celestron-Vixen C80-SP, a nice Made-in-Japan 80mm f/11 achromat on a Super Polaris mount with a heavy duty wood tripod. Right now, I'm mostly using it for piggyback photography with a DSLR.

The SP mount had no polar alignment scope, but I read on a forum that the current Celestron CG-5 / Synta EQ5 polar scopes fit. So I ordered a polar scope off ebay, and it works perfectly. Like it was meant to fit there. I guess Synta really did copy the SP and GP right down to the thread sizes. The mount is much easier to align now, I got polaris in there just so, and I had minimal drift error over 15 minutes on Orion.

Adventures with a DSLR

For my big christmas present, I bought a Canon EOS 60D kit from Costco, with the 18-200 IS zoom.

Last month, on a partyly cloudy full moon, I got the bright idea to point the camera at the night sky and take some time exposures with my 20mm f/2.8 lens.

4s at f/2.8, iSO 400

yosemite Outreach July 2011

Does anyone know if the camping site usually sits on semi-hard or concrete pads? The 2005 photo and comment mentioned campers were on concrete ground. Were bringing pads but maybe cots are better suited for this event.


I'm going to jot these useful formulas.   They were cribbed from various places.


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