Mark: I would recommend the book "The Dobsonian Telescope" by David Kriege and Richard Berry. If you are considering building an Obsession style telescope this book is a MUST. Give me a call or e-mail me and I will loan you my copy to look through. While it stops short or measured drawings it has step by step instructions on building your truss scope. In spite of the fact that I will most likely not have a Dobson type scope any time soon, maybe ever. I would not want to part with this book but I will make you a short term loan. Steve ----- Original Message ----- From: "Mark Shelton" < woodturninginc @yahoo.com> To: "Utah Astronomy" <utah-astronomy@mailman. xmission .com> Sent: Monday, January 24, 2011 4:08:05 PM Subject: Re: [Utah-astronomy] Mirror Hi, I will go out and clean the mirror tonight sometime and take a close look. I will let you know what it looks like. Thanks for the information Mark ________________________________ From: Jay Eads < jayleads @ gmail .com> To: Utah Astronomy <utah-astronomy@mailman. xmission .com> Sent: Mon, January 24, 2011 3:38:18 PM Subject: Re: [Utah-astronomy] Mirror Mark, Have you considered emailing Steve Dodds over at Nova Optical here in Herriman ? I know when my daughter and I get done figuring our 8" and 12" mirrors I'll have him coat them. I believe he can test the mirror for you. How old is the mirror and how do the coatings look? Jay On Mon, Jan 24, 2011 at 2:29 PM, Chuck Hards <chuck. hards @ gmail .com> wrote:
Mark, a quick look through a Ronchi grid will tell you everything. Likewise, before you part-out the Coulter , perform a star test. That will also tell you about the correction on the parabola.
I have owned many Coulter mirrors over the years, and never had a bad one.
On 1/24/11, Mark Shelton < woodturninginc @yahoo.com> wrote:
Hi, all
I have a question. I just acquired a 13.1 F4.5 Coulter dob. I am thinking about just using the mirror out of it and making my own version of a Obsession looking dob.
Is there a good way to tell if the mirror is worth the effort to make a dob built around it?
I have it out of the telescope and I can not see any defects so far in the mirror. ( have not looked really close at it yet.)
The Mirror sets in a kind of sling in the tube. Very Strange setup. I guess it was the way they made them in early 1980 or so.
If some one has a mirror cell to fit this size of mirror I would love to hear from you.
I really do not know what I should be looking for to check the mirror.
Any Suggestions would be appreciated.
Mark _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman. xmission .com http ://mailman. xmission .com/cgi-bin/mailman/ listinfo /utah-astronomy Visit the Photo Gallery: http :// www . slas .us/gallery2/main. php Visit the Wiki : http :// www . utahastronomy .com
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-- Jay Eads _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman. xmission .com http ://mailman. xmission .com/cgi-bin/mailman/ listinfo /utah-astronomy Visit the Photo Gallery: http :// www . slas .us/gallery2/main. php Visit the Wiki : http :// www . utahastronomy .com _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman. xmission .com http ://mailman. xmission .com/cgi-bin/mailman/ listinfo /utah-astronomy Visit the Photo Gallery: http :// www . slas .us/gallery2/main. php Visit the Wiki : http :// www . utahastronomy .com