RE: Focus indication

["Creager, Robert S" <CreagRS@LOUISVILLE.STORTEK.COM>]

This is an C/C++ Windows program I'm writing, not Qbasic.

Could you dumb down your explanation a bit :-)  I believe you're assuming
I've found a star in my window.  While I'm sure I can find a star, does it
make sense to find a 'good' star, or will just any old one do?  Marginal
sums?  Half power I get.  I guess I should of brought my AIP book today...

> -----Original Message-----
> From: aah@nofs.navy.mil [mailto:aah@nofs.navy.mil]
> Sent: Wednesday, June 13, 2001 11:29 AM
> To: tass@listserv.wwa.com
> Subject: Re: Focus indication
> 
> 
> Are you talking about additions to the Qbasic code to
> do this?
>   Calculation of the psf is not necessary.  The simple
> method is to find the marginal sums in x and y, find
> the center, and then march down until you reach the
> half-power points on both sides.  That gives you the
> fwhm to less than a pixel accuracy.
> Arne
>