How big? (was Re: ATM Advance in CCDs)

["Michael P. Lindner" <mikel@att.net>]

Clive Milne wrote:
> 
> Mike Lindner wrote....
> >I don't understand why this is a "breakthrough".
> 
> .... Compared to the old series KAF chips , it is.......

Thanks for the info.  I don't yet have a CCD camera, but would like one,
so I've been trying to learn about the different chips available.  I
have a question about pixel size.  I've read that the airy disk should
cover more than 1 pixel to avoid stars looking "blocky".  The airy disk
diameter for green light is about 2.44 x 550e-9 x f/ratio, or roughly
1.3 microns x f/ratio.  Many of the CCD chips seem to have 15 to 20
micron pixels.  Does that mean they work best at f/20 to f/30?  Please
tell me I did the math wrong!

--
Mike Lindner