Re: Re:ATM An Old TMs Simple Query

["Vladimir Galogaza" <vladimir.galogaza@zg.tel.hr>]

So scprach Richard:

> what is a good way to remove distortion from the image, and to correct
>measurements on the distorted image (assuming the exact center of the image
>is not located).

Some thoughts:

If distortion is due to optics and film mounting than it may be considered
constant for particular camera. If this is so I think than it can be
"calibrated out" if
it is well defined. So the question is how to calibrate deformations.
Can it be done by photographing well known dense star fields and compare
measured coordinates on the film with known coordinates of imaged stars
(say from Hyparchus measurements). With sufficient number of photos  and
stars
whole field can be mapped down and distortions found. Than distortions (
hopefully) can be
computed out from any later actual observation.
( Flaming appreciated)
Regards
Vladimir.