Re: ATM 11.2" F/2 Primary testing questions :)

["Tom & Lou Krajci" <krajcit@3lefties.com>]

> From: "James Lerch" <jlerch1@tampabay.rr.com>
>
> I actually did calculate the Coma for this project.
>...Here's a screen shot of the anticipated =
> Coma near the edge of the Chip, using the Full Aperture :
>
> http://lerch.no-ip.com/atm/coma.gif=20
>
> With the full aperture, about 80% of the light from a star will fall on =
> a single pixel. 95% will land on about 5*3 pixels, and 100% will land on =
> 16*14 pixels.  That is of course if I can figure such a beast, But I =
> won't know until I try ;)
>
> I'll probably use this scope to take some pretty pictures, but it's main =
> goal will be Astrometric Observations, which can probably live with the =
> Coma.

Have you checked with others doing astrometry concerning coma and
suitability for astrometry?  If you speak to folks that have done lots of
astrometry, and show them how much coma you anticipate at the edge of the
field, your focal length, pixel size, etc....they may be able to give you an
idea on whether or not your entire CCD field will be suitable for
astrometry, or to what level of accuracy, or what software will be needed to
handle the comatic images.

Tom Krajci