Where should I look for a cheap large-diameter telescope mirror?

I'm looking for an inexpensive telescope mirror to attempt some DIY Schlieren photography. I don't need a flawless one that you would put in a telescope and use in an observatory, I'm looking for the one that fell off the back of an astronomer's truck on the way up the mountain and got a scratch down one side and a nick in the silvering to make it worthless for astronomical observing. Any handy "old junk telescope parts" websites out there?

Or better yet, does anyone reading this have a decrepit old mirror sitting in their garage waiting for me to buy it from them?

Picture of Where should I look for a cheap large-diameter telescope mirror?
Yes, it has to be spherical. I have an 18" zeiss f2 mirror from a sclieren camera ... from a dumpster...no, its not for sale. I think you need a fairly precise surface. Try surplus shed. They are great guys. Try a big shaving mirror ??? Worth a shot. Make one ?
CameronSS (author)  steveastrouk8 years ago
Thanks for the note about spherical, I didn't realize that spherical/parabolic was an issue. I didn't mean that I don't need a precise surface, just that one with a couple dings that make it unsuitable for astronomy would still be fine for me. I'm not going to make a mirror! That requires a heck of a lot of patience, which I don't have.
Take you a day to make a 6" spherical mirror if you aren't really fussy about focal length. It'd be a BUSY day I'll grant you ! Steve
Prfesser8 years ago
See if www.surplusshed.com has what you're looking for. If memory serves, Schlieren photography works fine with a spherical mirror, you don't have to have the paraboloid that's normally desirable for astronomical observation. Ebay has telescope mirrors and some are fairly cheap, around $20. Depends on the size you're looking for. You might have to search for a while. Best -- Prfesser