The list is slow so here's a question (or two): What experience have people had regarding the workability of glass with different anneals? I'm not talking...
That depends on your experience an skill level. Almost nothing is too thin however the dificulity of creating a good figure goes up as they get thinner. More...
... There's no sharp demarcation between thick-enough and too-thin. Instead it's a gradual shading of increasing complexity and new techniques. My rule of...
This interesting item: http://tinyurl.com/2v82n8 for a 20" blank molding process, from the embeddedRF people, who've occasionally marketed (or at least hinted)...
... Might be tricky but sounds doable based on what Ive seen other do on the net. I recall more than one 16" out of 3/4" glass but your getting to the upper...
New to this group, first mirror and need a little advice if someone could spare a minute ... It appears that I am now quite close to a sphere, with the...
A little "moon walking" is to be expected. It looks like you are going forward but it turns out you aren"t. You can learn from going backwards. One of the...
As per your suggestion Jerry, I have replaced my shoes with oven mits and am currently watching an old Michael Jackson video. I will be ready for whatever...
... It will need an 18 or just possibly a 12 point, Plop optimized cell. Based on the idea (not experimentally validated) that Plop predicted flexure...
Yes, a 12 or 18 point cell will work fine. But I think the original question is not about support, but about making the mirror in the first place. It's not...
I was interested in both points actually, but crossing the first bridge first. That's the type of answer I was looking for. Thanks Mark. Tom W. ... use to ... ...
... May I suggest: http://tinyurl.com/3872nh This is a link to Mike Lockwood's web page on making laps and parabolizing with a full-size lap. It is excellent...
sorry for the spelling you probaly know what is it we have at the club and old but good 8 inch sh.. camera not used the lab at the observatory is not...
Jacques, The focal plane of the old 200mm f/1.5 Celestron Schmidt camera has a 300mm radius (it's the same as the focal length). A flat 8mm CCD chip will...
... Stiffness varies as the cube of thickness, so equivalent stiffness is obtained with the cube root of the ratio of moduli. In the units used in Plop, the...
When I run Tom Krajci's 12h cell design for a 14 inch diameter, 3/4 inch (19mm) thick fused silica mirror assuming f/5 and 55mm diameter secondary, I get 1.95...
Hello everyone, I just reached the point where the laser lights is no longer leaving no difraction on the surface. This is a 12.5" by 2" thick Pyrex bought...
Hi Roman, I tried to look at the site you have given but get a message saying it is unavailable due to having exceeded it's data transfer limit. Dave....
Hi Roman, Try turning the room light down, so your camera can't see through the glass to the inside and back of the blank. Then you should only see the ...
... limit. ... I moved the web content to my Verizon home page, this one should not bark about usage http://mysite.verizon.net/res7uy4g/ it's the first...
... Thanks Mark, I will try that, it's hard to do with grandchildren around ;). BTW thank you for all the fine work you have put out there for us beginners,...
Ah, I probably should have read your next post first... ;) There's a rule-of-thumb you can extract from PLOP about the ratios of fairly thin mirrors, and over...
just aclic in my mine I read this site http://storm.prohosting.com/~lisaphot/gil/flex/index.htm and compared to your problem maybe it is the solution make your...
Jacques, For myself I choose the "tormenting with the pitch lap" approach - to make a sphere or some intermediate conic section accurately enough for the...
Time to get back into the swing of things, I have been much to busy lately. Want to get my 10" back in shape after two years of collecting dust, I started to...
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