I'm guessing that blank will weigh much more than 100 pounds. The volume of the mirror is pi * r * r * h where r (radius) is 18 inches, and h (height) is 2.5...
Hi Bill; I do not have the total weight figure out but it the total mass of glass weight less then 150 pounds I will still be happy. I do not have a cost on...
Some ribbed blanks that are fused together suffer from "print-through" of the pattern into the front surface. This may be true even if the mirror has been...
Hi Gregg; This is still in the planning stage I will check into it. I do not known all the mechanical properties of BVC glass. Here is the web site for A.J....
I read on a webpage (http://www.oldham-optical.co.uk/Glass.htm) where BVC has a TCoE of 2.4-2.8 while Pyrex or equivalent is 3.2 and fused silica is 0.55, and...
Hi, I think the first step would be to find a mirror maker that will handle the BVC glass. I have a 18.5" BVC mirror and my mirror maker went through a lot of...
... But the ... slump ... Being the person who wrote that S&T article,having the blank evenly curved is far stiffer than one having a flat bottom.I never found...
... Do you know who made that mirror? I did a 14 inch fused cellular of pyrex written up in S&T,back in 1983, that when finished was stored in a metal garden...
Mike Lockwood did a 32" BVC recently: http://bi-staff.beckman.uiuc.edu/~melockwo/telescopes/holmes32/holmes32.html He does nice work. He did a 8.25" Minor...
Hi Dave; The only problem so far with the glass I found is you have to be careful when you are fine grinding at 5 micron because the glass and the tool if...
Hi Scott; This what I trying to get to!!! And I did find a book at our local library. And it is call Warm Glass: A complete guide to forming techniques fusing,...
I'd like to know if any of y'all big dob guys have seen them thar teenny G and H varmints *VISUALLY* in that thar M42 Trap and if you could give particulars of...
Hi Greg and the best of the season to you... this is a post I recently placed on the Obsession group - in a nut shell it is not easy! Recently I was invited to...
I'm limited to 14" or my friend's 15". E and F we see regularly but G and H in our aperture range, in our skies, are in the "fuhgetaboutit" category. There...
Likewise I can see e and f in DC just 1000 meters north of USNO pretty regularly with my O 15" Never a wisp of g or h, though. Steve Truitt ... [Non-text...
Greg, I have never done so, but a very respected local observer with a 15" Obsession recently told me that he had G and H flickering in- and out- of view at a...
Hi Greg, That's a yes here. G & H through a 22" F/6 at 830X using a Widescan 8mm and 2X Barlow from 6300 feet in Meyers, Calif. on an excellent night of...
Greg, On a night of exceptional transparency and seeing, I managed to view G and H (using averted vision) in my 12.5" at Mt. Pinos in SoCal (8350'). The night...
Hi, ... http://bi-staff.beckman.uiuc.edu/~melockwo/telescopes/holmes32/holmes32.html ... Thanks, Scott. My current machine could probably be configured to...
even in 61" I could not see H'! g. ... in ... and ... built ... it is ... At ... to ... Trapezium. ... out ... the ... these ... would ... nice ... NOT ... ...
Hi Mike; Please email at ghberry@... I need a diagonal mirror this spring. Thank You Gordon Berry ... From: Mike Lockwood To: bigdob@yahoogroups.com ...
Thanks all. It seems that mid teens on up G and H become *possible* but that even 60" isn't a guarantee. As usual it's the swimming pool over our heads which...
I've notice that on refractor groups they spend a lot of time talkng about a the Airy disk in reltaion to doubles and there's a lot of knowledgeable discussion...
Hi Greg, I think you have summed it up perfectly. In my experience it is rare to see Airy discs in telescopes larger than 8" -- let alone the average 'scope on...
Hi, ... In my experience, seeing them in a 6" F/8 reflector is not difficult so long as the optics are cooled off. I often see them in my 10" telescopes...
Gordon, ... Somehow the last part of your email got chopped off. You can try to post it again or you can find my private email address by searching through...
Yahoo deletes email addresses after the @ sign if you're reading messages on the group page. Gordon's email was ghberry(at)earthlink.net. -John ... ...
