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RE: Lots of Data
Thanks for the info Chris.
I've downloaded and installed the IRAF software on my Linux box, and will
run through their 'tutorials' soon. First problem I've encountered is the
lack of a param file for 'cl'. I'll browse their web site to see what I
need (unless someone sends me an e-mail before I find it)... I noticed that
IRAF has scripting abilities, so if I can figure out how to use the program,
it should go quickly (yeah, right).
Rob
>
> "Creager, Robert S" wrote:
> >
> > Why would Star (or any other software) need to change from
> the Mark III to
> > the Mark IV images? From what I understand, the Fits
> header contains all
> > the image information necessary to go about analyzing it.
> I know I'm
> > missing something...
>
> The Mark III camera is a "drift scan" camera. The simple explaination
> of "drift scan is that the camera is fixed. (does not track) but the
> digital "film" moves. The Mark IV is a conventional camera.
> The Mark IV
> also has a much larger image size.
>
> Yes, software could be written in a generalized way so that it could
> handle both a Mark III and a Mark IV image. IRAF (and I assume other
> image processing systems) is that generalized but the program we used
> for the Mark III, "star", is very specialized to the Make III
> and would
> need a lot of work to handle Mark IV images.
>
> >
> > I'll start working on a Perl script which will do the brief
> process Tom laid
> > out. I'll work on Linux, but the Perl scripts will be
> written to work on
> > Windows also (hopefully). Since IRAF is public domain with
> source, I'll
> > probably spend some time getting it to run on Linux and
> figuring out how it
> > works.
>
> While far from being an expert, I have some experiance with
> IRAF. First
> off it may not be so easy to mix Perl and IRAF. It can be done with
> the latest version of IRAF now but you loose a lot. IRAF has it's own
> scripting language. IRAF is also setup to process images in
> bulk. For
> example to apply a funtion to all images in a directory there is no
> need to loop. Just say "FunctionName *.FTS". This is faster too
> as the program "FunctionName" is only loaded once.
>
> IRAF has both an Intractive mode and a scripted mode. I find the way
> you work with IRAF is at first by hand interactively. Then once you
> know how to do something you create a little script. Later you may
> want to string a few of these little scripts to gether.into a bigger
> script. You work your way up.
>
> Using IRAF here is what I'd do:
>
> 1) use Perl or shell script to dump all the images into the "correct"
> directories for processing. Change file names as required so they all
> end in ".fits"
>
> 2) Patch up FITS headers to IRAF's liking.
>
> 3) Run "ccdproc" on the images. This will do all the dark/flat
> processing. trim the image section out, possibly remove cosmic rays
> and baisically give you a bunch of cleaned up images.
>
> 4) run one of the photometric packages in IRAF against all the
> "cleaned" images. There is both an Aperature and PSF fitting package.
> We can debate which is best forever or run both and compare results.
> The output of this step will be a star list for each image processed.
>
> 5) match each start list to a catalog to get good astrometry. I think
> the IRAF package to do this is called just "match".
>
> 6) Dump all the star lists into the site's database.
>
> If you need some help getting IRAF up and working on your PC let
> me know or post to the list and maybe some one else will help too.
> Be warned, IRAF is the 600 pound gorilla of Image Processing packages.
> I's big but don't let that stop you. You will not need to used even
> 1/4 of it as much of it is for stuff like spectrography and
> other things
> TASS does not do.
> >
> > 1. For each Fits image in a given location, do the following steps
> > 2. Parse Fits header to find sky location.
> > 3. Have IRAF (or other software) identify bright majors in image.
> > 4. Take stars found in 3 and compare against stellar
> catalog (presumably to
> > find exactly where we are in the sky so lower magnitude stars can be
> > matched?).
> > 5. Have IRAF (or other software) identify all (or to some
> magnitude) stars
> > in image.
> > 6. Correct magnitude of all stars found (maybe from stars
> used in 4).
> > 7. Spit out a list of stars.
> >
> > That about it for starters? I know that eventually dark
> and flat frames
> > will be needed, along with lots of other stuff, but it's a
> start... I'll
> > try to make the code easy to add new steps/change what
> software is used.
> >
> > Later,
> > Rob
> >
> --
> Chris Albertson home: chris@albertson-home.net
> Redondo Beach, California work: calbertson@primeadvantage.com
>