RE: DS9

["Albertson, Chris" <CAlbertson@primeadvantage.com>]

If the goal is simply to save space.  I dumb trick would be
to zero out all the pixels you don't want.  The FITS file
size would remain unchanged _but_ when you compress the file
those zeros will compress to next to nothing.  Well I did
say "dumb trick".

With IRAF clipping is trivial.  You simply copy the file as
in UNIX or DOS (copy aaa.FITS bbb.FITS)  But IRAF allows you
to specify a sub-region anyplace you are allowed to specify a
filename.  So for example 

    copy aaa.FITS[1000:1500,957:1248] smallimage.FITS

To trimm off the non-image pixels you would do something
like (but not quite)
    
    copy aaa.FITS$IMAGESEC trimmedimage.FITS

Now you can guess why people asked you for that IMAGESEC header line.


> -----Original Message-----
> From: Tom Droege [mailto:tdroege@veriomail.com]
> Sent: Saturday, April 14, 2001 5:48 AM
> To: Cary Chleborad; tass@listserv.wwa.com
> Subject: Re: DS9
> 
> 
> If I can't do this with DS9 then why does it have the box etc., 
> features.  What good is such a command if you can't cut and paste?
> 
> OK, if not DS9, then how about IRAF?  Could someone tell me 
> step by step 
> how to do this?  Assume that I have a bunch of files on a CD, 
> then how do I 
> read one and cut a piece out of the image and write it back to a file?
> 
> Tom Droege
> 
> 
> At 04:33 AM 4/14/01 -0700, you wrote:
> >To the best of my knowledge DS9 cannot do this.  Something 
> like CCD soft
> >from the Bisque brothers or MIRA from Axiom Research if you want
> >something a little more professional ( and $$$).
> >
> >-Cary
> >
> >Tom Droege wrote:
> > >
> > > Help!  I am using DS9 to look at the images with WCS 
> headers.  I want to be
> > > able to cut a small piece out of an image and write it to 
> a file with the
> > > fits header intact.
> > >
> > > I am running DS9 under windows.  I can mark a box around 
> the stuff I want,
> > > but I cannot find the commands to cut out this region and 
> write it to a 
> > file.
> > >
> > > Can anyone help?
> > >
> > > Tom Droege
> 
>