Posts Made By: Greg Shaffer

Richard L Schott said:

I placed an ad for a Celestron C-11 some weeks ago. However, only the photo and the name appear in the ad. There is nothing about price, history, condition which I had originally entered.
Any suggestions or help?

DS

Richard Keppler said:

Charles Stevenson said:

I guess this shouldn't come as a huge surprise considering people have been saying CCD is dead for awhile. I wonder which CMOS chips are good for deep sky?

http://www.baslerweb.com/en/news-press/sony-to-discontinue-all-ccd-sensors-in-march-2017/36619?utm_source=basler-newsletter&utm_medium=e-mail&utm_campaign=March-NL2015

and, so what? Please explain which astronomical CCD camera uses Sony CCD chips other than for entry level imaging and guiding? Pretty much everything I know about uses ON-KAF or e2V CCD chips. If you want to use CMOS chips for imaging, it has been going on pretty successfully for years. Ever heard of Canon EOS DSLR cameras? Nikon has some good ones too and while I have never looked into them, I think they may have started with the "D3100" series. Amazingly enough, so does Sony. Who would have thought?

Mark Volle said:

This is a multi-part question about compromises.
I have a 16" parabolic mirror - 3" thick pyrex - roughly 132" FL - it needs re-coated but seems OK.

Calculating the mount for such a mirror, it is clear that it will deform significantly even with a very complicated arrangement of support.

Has anyone tried "re-machining" a mirror like this into more of a truncated conical back? I calculate that I could remove more than 12 lbs off of the 45 lb mirror but am not sure what that would do to the shape of the front.

In theory, it would be easier to mount and would cool faster?

Mark