10″ Dobsonian Makeover Project

About 18 months ago, someone contacted CAAS about a 10″ Coulter Odyssey OTA that her brother had owned and asked about how to sell it.  That sparked an interest and I wound up buying it.  I made a quick and dirty mount for it, remember it was an OTA only, but once I got it assembled I realized that that for whatever reason the focuser was too close (or maybe it was too far) to come to focus.  Disappointed, I set it aside until another day.  Since that time I’ve been thinking about performing a makeover on it to turn it into a more compact (for storage at least) and usable scope.

I’ve done research and come up with ideas. Last weekend I did my first router work and cut an 18″ circle out of MDF.  This was actually meant to be a test of the process but when I was done it was pretty good so I may well use it.  Regardless this or another circle will be cut in half and probably hollowed out a bit to make the altitude bearings.  Hollowed out to save weight.

This afternoon I disassembled the old OTA bagging up the parts I want to bring forward to the new scope.  These are the focuser, the secondary, the telrad finder, and the primary (of course). The primary was well attached to the original MDF mirror cell with silicone that though pliable was not separating easily. I finally decided I was going to damage the mirror if I didn’t try another way so mirror and MDF cell are soaking in warm soapy water right now. I hope to be able to remove the ruined cell easily when done and have a clean mirror to boot.  Making a new cell should be straight forward.

The original secondary and holder are rather plain, a straight rod that runs across the tube with a mirror attached.  Of course, Coulter was in bang for the buck business and you can’t expect Obsession at Odyssey prices. It works and I might try to use it at least to begin with but that may have to be replaced.

The focuser is an aftermarket ScopeStuff Crayford model and might be the most valuable part after the mirror itself so its a keeper.

A couple years ago, someone gave me the carousel part of a Dobsonian.  Probably a 12″. I’m not obligated the use it but that would be a part I didn’t have to make if I do.  The size would make for stability but it might also look a 6 year old walking around in his dad’s shoes.  Of course in my case dad and I had the same size feet when I was six.

More later.

Below is the 18″ MDF round that I cut.MDF round


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