http://tech.groups.yahoo.com/group/NewtonianReflector/ NewtonianReflector Fri, 06 Nov 2009 15:01:38 GMT john nassr http://tech.groups.yahoo.com/group/NewtonianReflector/message/1381 http://tech.groups.yahoo.com/group/NewtonianReflector/message/1381 Peter, Using silicone glue "blobs" around 1" in diameter on each of the 27 flotation points of a mirror cell should properly hold a 24" mirror on an equatorial Fri, 06 Nov 2009 06:28:31 GMT mhholl@... http://tech.groups.yahoo.com/group/NewtonianReflector/message/1380 http://tech.groups.yahoo.com/group/NewtonianReflector/message/1380 In a message dated 11/5/2009 10:05:29 PM Pacific Standard Time, ... Assuming the "large, fast" Newt mirror is also thin (less than 6/1 width/thickness ratio), Fri, 06 Nov 2009 06:05:14 GMT Peter R http://tech.groups.yahoo.com/group/NewtonianReflector/message/1379 http://tech.groups.yahoo.com/group/NewtonianReflector/message/1379 Hi all, My first posting to this group. I was interested in the opinion of others with respect to the best mirror cell design for a large, fast(f/3-4) Fri, 23 Oct 2009 10:47:44 GMT john nassr http://tech.groups.yahoo.com/group/NewtonianReflector/message/1378 http://tech.groups.yahoo.com/group/NewtonianReflector/message/1378 Mick, Thanks for the clarification. Cutting a cylinder 45 degrees is what I had in mind for my secondary holder. Best regards, John ... From: mhholl@... Fri, 23 Oct 2009 05:14:14 GMT mhholl@... http://tech.groups.yahoo.com/group/NewtonianReflector/message/1377 http://tech.groups.yahoo.com/group/NewtonianReflector/message/1377 Subj: Re: [NewtonianReflector] Formula for determining secondary mirror's major axi... Date: 10/22/2009 3:24:53 PM Pacific Daylight Time From: Fri, 23 Oct 2009 01:10:04 GMT mhholl@... http://tech.groups.yahoo.com/group/NewtonianReflector/message/1376 http://tech.groups.yahoo.com/group/NewtonianReflector/message/1376 In a message dated 10/22/2009 3:24:53 PM Pacific Daylight Time, ... John - glad to be of help. Mick Hollimon 22 Oct 09 6:10 PM PDT USA [Non-text portions of Thu, 22 Oct 2009 22:24:40 GMT john nassr http://tech.groups.yahoo.com/group/NewtonianReflector/message/1375 http://tech.groups.yahoo.com/group/NewtonianReflector/message/1375 Mick, I have a big smile on my face! Thank you for the formula. I can now better proceed with the assembly of my home made scope. John ... From: mhholl@... Thu, 22 Oct 2009 17:17:03 GMT mhholl@... http://tech.groups.yahoo.com/group/NewtonianReflector/message/1374 http://tech.groups.yahoo.com/group/NewtonianReflector/message/1374 In a message dated 10/22/2009 2:56:45 AM Pacific Daylight Time, ... John - the major axis of an ellipse is square-root-of-2 (approx. 1.414) times the minor Thu, 22 Oct 2009 09:56:35 GMT jnassr2000 http://tech.groups.yahoo.com/group/NewtonianReflector/message/1373 http://tech.groups.yahoo.com/group/NewtonianReflector/message/1373 Hello, What please is the formula for determining the length of the major axis of a secondary mirror? I need to find the exact center of my secondary mirror Sun, 11 Oct 2009 21:21:35 GMT patconlon http://tech.groups.yahoo.com/group/NewtonianReflector/message/1372 http://tech.groups.yahoo.com/group/NewtonianReflector/message/1372 ... Yes 15mm is all I have to play with the mirror is 150mm O. D. OF tube is 167mm so alowing 2mm for tube thickness 15mm is all I am left with or possible Sun, 11 Oct 2009 17:26:31 GMT tincanandstring http://tech.groups.yahoo.com/group/NewtonianReflector/message/1371 http://tech.groups.yahoo.com/group/NewtonianReflector/message/1371 Sorry, can't help you there, I'm a hammer and tongs (actually power saw) kind of guy. It seems that you have more resources for simple metal work like that in Sun, 11 Oct 2009 12:01:08 GMT patconlon conlon http://tech.groups.yahoo.com/group/NewtonianReflector/message/1370 http://tech.groups.yahoo.com/group/NewtonianReflector/message/1370 Thanks Frank for the very informative reply I like the idea of foam to act as baffels  I have about 15 mm. to work with so I think it would work, cutting the Sat, 10 Oct 2009 16:01:06 GMT tincanandstring http://tech.groups.yahoo.com/group/NewtonianReflector/message/1369 http://tech.groups.yahoo.com/group/NewtonianReflector/message/1369 Welcome, Pat. I had the same issue on my new-to-me 10" Discovery-built Orion PDSE Dob. I had changed out the focuser from the abysmally slow helical to an R&P Fri, 09 Oct 2009 14:33:53 GMT patconlon http://tech.groups.yahoo.com/group/NewtonianReflector/message/1368 http://tech.groups.yahoo.com/group/NewtonianReflector/message/1368 Hello everyone I am new to this group so this is my first post. I would like to know what the group members think of Parallax Newtonian telescopes they seem to Thu, 10 Sep 2009 00:48:49 GMT Randy Smith http://tech.groups.yahoo.com/group/NewtonianReflector/message/1367 http://tech.groups.yahoo.com/group/NewtonianReflector/message/1367 The Ozone layer is a good absorber of UV not of visible light. The ozone layer is essentially transparent to visible light so, the color of objects in the sky