mirrors - buy them where ?

[AussieBill (Bill)]

Does anybody here make their own telescopes without grinding their own mirrors ?

Given the prices that I have seen for blank glass and finished mirrors on ebay am amazed that anybody can make their own telescopes at a price comparable with the completed telescopes available in the shops.

Am I missing something here ?

Am somewhat daunted by the thought of grinding and silvering my own mirror.

Does anybody here make their own telescopes without grinding their own mirrors ? Where did you buy the mirrors ?

Bill

[glend (Glen)]

I have made a 10" f5 carbon strut newt, used GSO mirrors sourced from Bintel.

[torana68 (Roger)]

Originally Posted by AussieBill

.......................Am I missing something here ?
.......................Bill

There is a quality difference, cheap Chinese $, low quality fuzzy view, better Chinese $$ you'll see more probs still a bit fuzzy and lacking detail compared to best quality mirrors $$$$$$ (some of which could be hand made by an amateur) you'll see lots of detail no fuzzy view . Difference in price is something like A$300 to A$3000 (8") for the mirror set.
Someone will come along shortly with some Maths and maybe some charts and optical info but that covers it pretty well I think

[glend (Glen)]

Originally Posted by torana68

There is a quality difference, cheap Chinese $, low quality fuzzy view, better Chinese $$ you'll see more probs still a bit fuzzy and lacking detail compared to best quality mirrors $$$$$$ (some of which could be hand made by an amateur) you'll see lots of detail no fuzzy view . Difference in price is something like A$300 to A$3000 (8") for the mirror set.
Someone will come along shortly with some Maths and maybe some charts and optical info but that covers it pretty well I think

That is just wrong, have you read anything about how GSO mirrors ( which are Taiwanese actually) are made these days and the quality they are delivering. If Bill is thinking of building his scope, GSO mirrors are the most cost effective/quality on the market. Certainly, don't buy mirrors off Aliexpress from unknown sources. If you buy GSO mirrors from Bintel you always have the option of returning it if its rubbish, but it won't be.

[torana68 (Roger)]

Gee touchy much? I don't mention any brand names nor did I say don't buy chinese ...... Go have a coffee 😳

[SkyWatch (Dean)]

I bought a 12" f5 GSO mirror from Bintel a few years back (after some low-life stole all my gear, including my 10" dob that I ground myself).
The specs were better for the stand-alone mirror than for the one in the completed GSO scope (I can't remember offhand what they claimed, sorry: although claimed specs don't tell the full story).
It is a very good mirror and for way cheaper than if I ground it myself. Foucault testing shows text-book images for a well-corrected mirror. Star testing is pretty much spot-on, and high power viewing of Jupiter and Saturn show nice, crisp detail.
I don't know whether Bintel still source them: when I bought mine it was a "run-out" price as the last of their stock at that time. I think Matthew Lovell can source mirrors (http://www.telescopes-astronomy.com.au)
If you want the high-end, guaranteed, hand figured stuff you probably need to check out Zambuto (http://zambutomirrors.com/mirrors.html), Mike Lockwood (http://www.loptics.com/info.html) or one of the other US makers (Galaxy?); I don't think anyone makes them commercially in Oz anymore.

Good luck,

Dean

[leon]

Yes indeed,you can buy a mirror these days very cheaply, however grinding your own and seeing it collect light for the first time is worth more.

I did a 8 inch many years ago, and although not perfect it was a great experience.

Leon

[torana68 (Roger)]

Originally Posted by leon

Yes indeed,you can buy a mirror these days very cheaply, however grinding your own and seeing it collect light for the first time is worth more.
I did a 8 inch many years ago, and although not perfect it was a great experience. Leon

definitely, feels better to do than buy, but if you cant do dont buy cheap rubbish