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Cassegrain Assembly

Started by Walter, 10/03/2013 04:42PM
Posted 10/03/2013 04:42PM Opening Post
Our club has received the gift of a 12.5" Cassegrain mirror set. I have determined that the primary is f/4 but don't know what the secondary magnification is. It is about 4 inches in diameter.
I have made quite a few newts and many I ground and polished the mirrors, but have no experience with Cassegrain optics.
What I would like to find out is how difficult it would be to assemble one and where would I get the proper parts like mirror cells and secondary holders for cass optics. I have looked at the obvious websites and none are listed that I could find.
Any hints would be greatly appreciated. Another thought is to simply sell the optics and purchase something else. Any thoughts on the possible value of the mirror set?

Walt
Posted 10/04/2013 08:16AM | Edited 10/04/2013 08:19AM #1
Try here: http://bobmay.astronomy.net/CassNotes/index.htm

And here: http://www.alpo-astronomy.org/jbeish/Cass_Equ.pdf

Any idea who made the optic set? Are there any markings on the back or edge of the primary/secondary?

Keith

Scopejunkie



40 year old restored C14 with recirculating cooling

w/Skywatcher DOB GOTO Conversion (CPC14)
Posted 10/04/2013 05:13PM | Edited 10/04/2013 05:16PM #2
Astro Systems makes Cassegrain secondary holders that fit their spiders. For my 10.25" I got the primary cell from Optical Supports with mods to their standard design being perforation in the mirror side plate and change to the fan mounting pattern to accept a Feathertouch flat base. Hard part was the spacing so I got telescoping aluminum tubing from DX Engineering and made a truss scope to work out the mirror spacing and focuser position.

Dave

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