Does any1 still grind their own mirrors?????

[Glasspusher]

Andrew, the reason I am advocating the star test is that it does not require additional equipment in order to be performed. The skills needed to perform the test can be learned relatively easily in a short period of time. ALSO, if you are making your own telescope you will be able to put the optics in the tube to carry out the star test, this means you do not have to rely on bench tests to complete the optics. Professional opticians do not have the time to wait for clear nights in order to test optics, also they often do not have the tube assembly in order to perform the star test.

John

[FraserClarke]

That's very interesting - I was aware that Herschel tested his scopes by observation but thought the modern way was Foucault testing etc. This approach sounds very appealing - even if it means having to wait for a clear night.

Star testing for manufacture of professional telescopes certainly lasted up to the 200-inch on Palomar (1947), and possibly even later.

Indeed, all modern professional telescopes are star tested in operation. In fact, most of them run in a mode where they are effectively star testing the telescope continuously, by measuring the image quality of the guide star, and adjusting the optics (literally pushing and pulling the mirrors) to maximise the performance.

Modern optical shop testing would generally use an interferometer.

A star test is the ultimate test though, because it tests the whole system (i.e. including the mirror supports and telescope mount) rather than just the optics.

[weuexam]

... and if I had to do it again, I'd start smaller with a 12"-14" mirror.

I joined the Camden Telescope making society which was beneficial, but not essential. ...

I am thinking about a 6" for my first attempt but living in a flat I do not have a workshop.

Does one actually do the grinding at the Camden Telescope society?

Thanks in advance

Austin