Hi, This has probably been debated before but I'll ask anyway. Since completing it several months ago, I have been enjoying using my 16'' version of Mel's...
Well... I build and sell telescopes that don't use shrouds, so I will admit a bias. But I suggest you try it for yourself and see. You might want to make...
Tim I'm not going into the baffles-n-contrast debate, but I am a firm believer in protecting the mirror from STUFF. I say number 1, but maybe a breathable...
I recall that i did some sensitivity evaluations, but on the 2" thickness. I am not surprised of you findings: 1) they agree with the overall amount of...
I have a more detailed analysis of my earlier latteral testing. I discovered that what I had measured was not the difference between two and one peg support....
Tim, From what you said about the baffling you've done on your scope, it seems that you've gone to considerable trouble to prevent stray light from entering...
I can agree with a shroud protecting the primary from stuff. On my 12" truss Dob I often use a lawn garbage bag with the closed end cut off. It slides down...
Compliments! You hev shown that the positon of the support may cause astigmatins in the range -0.7 to + 0.7 waves (thus discussion of differente designs that...
Very interesting study Dale ! It is now clear for me that the astigmatism problem I have on my 24" 1.6" thick mirror is certainly due to a problem of placement...
Raphaël GUINAMARD
rguinamard@...
Dec 2, 2006 4:56 pm
16266
Mauro, Just a slight correction to your statment. The astigmatism PV wavefront range is .7 not -.7 to +.7. I realized I have the data to analyze trefoil. I...
I meant the range you can control: that by moving the support point you can achieve from -0.7 waves PV (vertical diameter wrt horizontal diameter, or 0.7 waves...
Mauro, Thank your for the clarification. I understand now. Dale ... you can achieve from ... waves horizontal to vertical) ... horizontal) when the ... ...
Here is my analysis of trefoil caused by 2 peg lateral support. http://doeason.home.comcast.net/lateral_test/trefoil.pdf This should be studied further to see...
Dale, I have a 20" Obsession with a Galaxy mirror. I've noticed that at very high power, sometimes, I see a bit of astigmatism in my mirror. Also, I have a...
Yes a sling causes similar distortion if not placed on the mirror's center of mass. I once tested an 18" obsession mirror it was surprising how important...
I have no idea whether baffling and controlling light scatter is a good idea or a bad idea, I note simply, that in the refractor world it is a matter of high...
Tim, That's a beautiful looking scope. I'm curious. Has your primary ever dewed up, with that exposure to the sky? I'd bet you won't notice a thing in terms of...
We notice a difference when we do not use the shroud on the Eastern Seaboard of the US. Above 50% humidity or so, after a couple hours the shroud protects the...
... Yes. With a refractor the exit pupil is looking straight up the optical train - at the sky and anything else up there. The low incidence of angle along...
... surprise surprise... I have done a quick check for my 16x2 mirror. I have considered the restraint to be concentrated at the back point of the lower mirror...
... Most of this thread has been above my head, but if your mirror was distorted by a 1/2 wave, wouldn't you notice that at the eyepiece? That's pretty...
Hi, There is nothing special about refractors. A couple of years ago I looked through Peter Ceravol'os open refractor. It only had lenses and baffles (no tube)...
http://doeason.home.comcast.net/lateral_test/sling_study.pdf Some have asked that I do a study of the sling for supporting thin mirrors. Here it is. I had a...
Yes an experienced observer and star tester would be able to see the error. This was done at worst case simulating the mirror pointing at the horizon. As you...
... There's still plenty of room in the photos section. -John ____________________________________________________________________________________ Do you...
... exactly ath ... NO!! 0.5 waves is the result of calculations IN CASE the mirror is resting on ONE pont located at the backplane on the lower edge. In fact...
... Exactly: i made a quck simulation which was intended to reproduce Dale's case with the support point near the back plane. Dale finds 0.7 waves for a 1"...
Which folder is it in? I can't find it. -John ... ____________________________________________________________________________________ Yahoo! Music Unlimited ...
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