I have a 250mm F5 telescope primary mirror for sale .
The blank is Schott Suprax ( a kind of low expansion Boroslicate 34mm thick ) .
The mirror is ex ASTRO OPTICS . It has never been coated. A good mate of mine (
) has tested it under double pass autocollimation and Null star test at high magnification .
It has a very smooth figure , superb polish , no turned edge under knife edge, and shows an excellent star test. The owner , whether using it for a replacement mirror in a chinese scope or a new ATM project would be thrilled with its performance .
It has never been coated . I can deliver it to CQin Pty Ltd for a superb Quartz protected aluminium which will cost you around $270 . CQin can ship to you from Campsie.
I am asking $450 ONO for the uncoated mirror . Direct Funds deposit or Paypal preferred.
See below for double pass Ronchigram under auto-collimation with a 200 line Ronch grating. The slight bend on the bands right in the middle is just a heat plume from the 550nm frequency laser diode light source.