"If I say something in the forest and my wife isn't there to hear it, am I still wrong?"
20" homebuilt truss dob 6" watson refractor
Quote:That mirror is a second surface mirror. It is also not a rigid mirror as it is only 1/4" or so thick. Not a premium optic.dan
Ex Oriente, astrum ---------------------- From the day you are born 'til you ride in a hearse, There's nothing so bad that it couldn't be worse!
8" Criterion Dynamax 6" Homebuilt F/10 Newt 6" F/8 Jaegers 127mm F/5.5 SS Assembly Various 60 mm scopes in many states of repair 8' Dome Observitory
Homemade 'scopes 8"f/7,6" f/5", 6"f/4, 4.25" Schiefspiegler,60mm Coronagraph,60mm H-alpha system, 4.25" White-light Solar Newtonian,solar spectroscope, 4" f/12, 4.5" f/16 & 6" f/12 Schupmann Medial refractors, 4" Celestar, 19 Stellafane awards 9 in optics Engineering = Taking what you have and making what you need.
Quote:Good idea, at least the kernel. The specific application needs design to address each one of those problems. Just tune it up a little bit and make it really BIG. Yeah, its not accurate to millionths of an inch but it has a 2 meter aperature! I think a camera at the focus would be the best method.Mylar's got potential!
Quote:I came across this and thought it might be good for making a cheap Dobsonian telescope. Do you think this would work well for making the primary mirror?
-DannyMy warehouseMy Channel
Quote: that guy is crazy, did you see his other videos. before I clicked the link I thought I wonder if it's that crazy guy doing it and I clicked the link and viola.He's so crazy. watch him cut a circle on a table saw. He's really crazy.
Quote:Henry Ford never hired experts, because they were always telling him what couldn't be done. Instead he found those who weren't aware that a task was impossible so they could do it. Think about it. Its not impossible. There's a solution for each of those problems.
Quote:Quote: that guy is crazy, did you see his other videos. before I clicked the link I thought I wonder if it's that crazy guy doing it and I clicked the link and viola.He's so crazy. watch him cut a circle on a table saw. He's really crazy. Actually it is a very good method for cutting circles, have done it for many years IMO gives a better circle than a router.What does scare me about his methods is cutting from the side of the saw opposite from the fence, Now That IS an accident waiting to happen!
Quote: Gavin article is in May 1979 SKy and Tel, "Aluminized Mylar as a Flux Collector" Here is a link to more recent article about the idea. At conclusion of the article, the best figure that they could produce had 10 waves of error in it. http://www.gravic.com/graviclabs/pdf/papers-altz/Alt%20Az%2024%20Holenstein-P... - Dave
Quote: Can someone please tell me or link me to instructions on how to do a Ronchi/Foucault Test or something equivalent that I can do for cheap?
Quote: The extreme accuracy required for a TINY 8" mirror would vanish when that mirror was the size of the one on Mt. Palomar (the Hale 200") because the aperature would win and cancel the errors of the less than micro-correct surface. Even if it was only 50% accurate you would still get a whopping eye-full of astronomic goodness
Quote:Here's Maurice Gavin's website that details his 21" aluminized Mylar mirror telescope that was featured in the May 1979 issue of Sky & Telescope:http://home.freeuk.com/m.gavin/flux.htm
Quote:Quote:Here's Maurice Gavin's website that details his 21" aluminized Mylar mirror telescope that was featured in the May 1979 issue of Sky & Telescope:http://home.freeuk.com/m.gavin/flux.htm Note that Mr. Gavin doesn't refer to his creation as a telescope but rather as a flux collector. It is stated in the article that this scope is not suitable for viewing. If you look at the image of the sun shown in the article you can see why. dan
Jc ATM 10" F6.1, 1/25th wave spec (max wavefront error +/- 1/12.6 in zone 4 of 6, sodium light ), 6" F7 spec, 127mm F9.4 achro Refractor, Criterion DX8, 10 x 50 bin, SP mount/Synscan goto. ETX80 (finder) Canon 20D, PST DSI 1, Butenschön 125mm F13.4 refractor, diy spectroscope and curiosity
Quote: The biggest problem I see is finding a large enough place to store it.