echelle aperture trimming before combining

[Guest]

Hi -

About 10 years ago Frank Valdez had written for me a short .cl routine
with which I could trim the esges of each aperture in an echelle image
before combining all the apertures into a long spectrum. This is because
at the edges of every order the SNR is low and I would like to remove
those parts before combining.

Needless to say I have lost the nice little routine and I cannot find a
similar routne in my iraf system. Can you help?

Thanks,
Orsola

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Orsola De Marco, PhD Tel: +1 (212) 496-3444
Department of Astrophysics Fax: +1 (212) 769-5007
American Museum of Natural History research.amnh.org/~orsola/
Central Park West at 79th Street
New York, NY 10024
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++


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[Guest]

From: Orsola <orsola@amnh.org>
Date: August 15, 2005 8:51:31 AM MST
To: iraf@noao.edu
Subject: echelle aperture trimming before combining



Hi -

About 10 years ago Frank Valdez had written for me a short .cl
routine with which I could trim the esges of each aperture in an
echelle image before combining all the apertures into a long
spectrum. This is because at the edges of every order the SNR is low
and I would like to remove those parts before combining.

Needless to say I have lost the nice little routine and I cannot find
a similar routne in my iraf system. Can you help?

Thanks,
Orsola

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++++
Orsola De Marco, PhD Tel: +1 (212) 496-3444
Department of Astrophysics Fax: +1 (212) 769-5007
American Museum of Natural History research.amnh.org/~orsola/
Central Park West at 79th Street
New York, NY 10024
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++++



From: Frank Valdes <valdes@noao.edu>
Date: August 26, 2005 11:15:02 AM MST
To: Orsola <orsola@amnh.org>
Subject: Re: echelle aperture trimming before combining


Hi Orsola,

I don't recall the script and I don't understand what you are after.
I would be glad to give you a script if you can described in more
detail what you need. Are you talking about combining 1D extracted
echelle orders but without using the first and last parts of the
data in each order? If you can send me a sample file (you can ftp to
iraf.noao.edu in the pub directory and let me know) or put it in a
local directory accessible by ftp or http.

The tools I think are needed for the 1D case are SCOPY and SCOMBINE.
If you are talking about triming the edges of the 2D orders that
would be a different thing which would involved using tasks in the
APEXTRACT (or equivalently the ECHELLE) package.

Yours,
Frank Valdes


From: Orsola <orsola@amnh.org>
Date: August 26, 2005 12:45:48 PM MST
To: Frank Valdes <valdes@noao.edu>
Subject: Re: echelle aperture trimming before combining


Dear Frank, thanks for getting back to me. Indeed what I want to do
is what you understand, namely, to cut off the ends of each order
before combining them into a single long spectrum. The ends are
funny, have a lower SNR and often bend unnaturally.

Now, I have got around the problem by creating a cl script that
copies the central parts of each order from the .ms. image into
individual files. This effectively trims each oder. Then the script
combines all these different files into single file containing a
continuous spectrum. Then it deletes all the individual files.

So, I think I am OK, unless you have a better suggestion.

Thanks again,
best, Orsola

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++++
Orsola De Marco, PhD Tel: +1 (212) 496-3444
Department of Astrophysics Fax: +1 (212) 769-5007
American Museum of Natural History research.amnh.org/~orsola/
Central Park West at 79th Street
New York, NY 10024
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++++


From: Frank Valdes <valdes@noao.edu>
Date: August 26, 2005 12:49:18 PM MST
To: Orsola <orsola@amnh.org>
Subject: Re: echelle aperture trimming before combining


Dear Orsola,

Your approach sounds fine.

Best wishes,
Frank



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