iraf.net

Dear Jeanette Barnes
I do not know if you are still involved with IRAF. If you are not I
appologise for taking your time and wonder if you could forward my
message.
There is a facility in TV called RGB which in theory allows one to
load three seperate images and display them simultaneously as red
green and blue. This is a very useful facility but does not work on
our sun stations. It comes back with a message like not supported
by stdimage. I have talked to some of the pundits around here like
Bob Thompson and Tim Wilkins and they do not think it will work and
it is rather difficult to do.
Can you please tell me what chance there might be of implementing
such a system as it would be incredibly useful.
Happy Christmas and a Merry New year and all that
Very Best Wishes
Robin Catchpole

Hello Kevin -Yes - your first message was received and answered. Things must have been
lost in the mail. I may have sent it to the wrong address. Hope you
do get this reply.Jeannette---------
>From jbarnes Thu Dec 19 06:35:58 1991
To: kevin@qmw.ac.uk
Subject: Re: IRAF status (SPARCStations)Hello Kevin -

The tape that you have marked "SunOS4/IRAF Version 2.9.1 EXPORT" is the
current IRAF. The IRAF system that you have is configured to run with
SunView using GTERM and IMTOOL as the terminal/graphics and image display
windows, respectively [these tools are included with IRAF].

But you can certainly configure IRAF to run with OW. In that case you could
use xterm (X Windows) or GTERM for your terminal/graphics window and
SAOimage (X Windows) or IMTOOL for your image display window since OW
allows you to run SunView and X Windows together. Several of the programmers
running OW here prefer the GTERM/SAOimage combination.

SAOimage is not included with your IRAF distribution but you can pick it
up from our network archive and install it independently of the IRAF
installation.

% ftp iraf.noao.edu [or 140.252.1.1]
ftp> log in as anonymous
ftp> use your last name as the password
ftp> cd iraf.old
ftp> get readme.saoimage
ftp> binary
ftp> get saoimage.tar.ZLet us know if you need further assistance.Jeannette Barnes (iraf@noao.edu)

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Q:Is there any iraf-compatible software
specifically designed for optical
polarimetry data?tom jarrett

Hi Tom,
It may not be quite what you're looking for but there are several
polarimetry tasks in the STSDAS HSP and TIMESERIES packages. You can use
the task REFERENCES as in "cl> refer polarimetry" to get a list of tasks
that have the word 'polarimetry' in their help header. If you haven't
got stsdas installed it's available via anonymous ftp from stsci.edu.
Hope this helps,Mike Fitzpatrick

Yo, Tom, I see that Mike has referred you to STSDAS - I'm not familiar
with what they have to offer in this arena.> Is there any iraf-compatible software specifically designed for
> optical polarimetry data? There is a task I wrote in our local package that may do what
you want. (What precisely is that, by the way?) It will process
either three or four images taken through a polarizer that has
been stepped through 45 degree increments, and generate the Stokes,
fractional linear polarization, and polarization angle images. Let me know if you want more info.Rob

Tom,> Your routine Linpol looks pretty good to me. One dumb question
> though ... the images contain stars, so how does linpol extract
> the stars and compute the stellar fluxes from which the Stokes
> parameters are derived? I must be missing something. Ah, the misunderstandings that arise when a problem is not fully
elucidated at the beginning. Lacking a full explanation, I
presumed that you were interested in surface polarimetry, not
point source polarimetry. If all you want is the linear polarization of point sources, by far
the simplest approach is to derive or dig up the Stokes relations
for even pi/4 intervals and apply them directly to the results of
the numerical aperture photometry. I would use apphot (for instance)
to accumulate the photometric measurements from each of the four
frames and then apply the rather simple Stokes relations with a
simple script or program, or even with just a calculator. The linpol task assumes that you are interested in the pixel-by-pixel
polarization of the image. This is scientifically interesting for
numerous reasons - say, for deciphering the illuminating star of some
reflection nebulosity. I suppose that you could apply linpol to the
entire frame and then perform photometry on the output, but the
signal to noise would be likely to get you.Rob