iraf.net

From: Rodney Guimaraes <guimarae@iap.fr>
Date: May 25, 2005 2:03:30 AM MST
Resent-To: Frank Valdes <valdes@noao.edu>
To: Mike Fitzpatrick <fitz@noao.edu>
Subject: Echelle image masking (fwd)
Mike Fitzpatrick wrote:> Hi Rodney,
> The SCOPY task can certainly extract an interval from a spectrum
> and create a new image. I'm not sure quite what the rest of your
> question
> means though: Do you want the area outside of the interval set to
> 1, or
> do you literally want to add 1 to the endpoint of the extracted
> interval?
> The SARITH task can be used to perform arithmetic operations on
> spectra
> in batch mode, this can also be done interactively using the SPLOT
> task
> (see the help pages for both). If you need a batch solution to
> process
> many spectra you may need to write a small script to combine the
> various
> operations (see ftp://iraf.noao.edu/iraf/docs/script.ps.Z for a script
> tutorial doc), but I'm not aware of anything in the system which does
> exactly what you ask.
> Others in the group will see this message and may also offer a
> suggestion. Hope this helps, let us know if you still have questions.
>
>
> Cheers,
> Mike Fitzpatrick
>
>
Hi Mike,Thanks for your quick answer.
I used IMCOPY to extract an echelle from my spectrum and after IMREPLACE
(Replace a range of pixel values with a constant) to set 1 in some area
of my new image created with IMCOPY. My problem is I would like to use
IMREPLACE directly on my echelle spectrum, i.e., do IMREPLACE without
extract an echelle from my espectrum. Is it possible???
the command that I used is:imreplace <filename> [interval] valuebut I would like to do something like :imreplace <filename>[*, echelle] [interval] value
it doesn't work. Maybe I need to split the spectrum in all the echelles
, use IMREPLACE in an echelle and after put all the echelles together.
Can you told me how to do this??
Thanks a lotyours sincerely,Rodney
From: Frank Valdes <valdes@noao.edu>
Date: June 16, 2005 9:32:56 AM MST
To: Rodney Guimaraes <guimarae@iap.fr>
Subject: Re: Echelle image masking (fwd)
Hello Rodney,Mike forwarded you question to me and the delay in responding is my
fault. I am not completely clear on some points. When you say
echelle spectrum I think you mean the extracted "multispec" format,
which sometimes has a .ec extension in the filename. In this case,
while the spectra software treats this format as a collection of
spectra, other IRAF tasks simply see a multidimensional image (2 or 3
dimensions) and don't even know that each
row is a "spectrum". So if I understand that you want to replace
certain values in
each spectrum but each spectrum has to have a different value then
you would use
image sections that address each line: ec> imreplace <filename>[*,1] value # First order in the
file
ec> imreplace <filename>[*,2] value # Second orderIf the file is 3D because of the extra information like the S/N you
would use something
like ec> imreplace <filename[*,1,1] valueThe key thing here is understanding the structure of the extracted
echelle format
as column=wavelength, row=order, plane=(spectrum, raw spectrum, ...)
and the
way to use image sections.It is possible you are referring to the 2D observational echelle
image before extraction. In this case it would be hard to do
anything general other than specifically identifying
pixels or ranges of pixels to replace.Let me know if I can explain this any better or if you have
questions. A more specific example would also help me understand
your need.Yours,
Frank Valdes