iraf.net

Hi Jeanette (or whoever) -- I've come across a problem on IUE work that may be easiest
to tackle with IRAF. Unfortunately, time is fairly critical
here so it would even help if you can point me in the right
direction or tell me who to talk to. It looks to me that this
be a matter for digiphot/dao/psf to solv. For our final archive high dispersion work we are remapping
pixels from one geometry to another (rotation, etc.) and some
time ago the decision was reached to use an algorithm called the
Shepard method to do this. Of course, our pixels have a finite
size, and so the remapping imposes a smoothing. What we would
like to do is to measure the amount of smoothing caused by this. To estimate this smoothing, we have set up a simple grid
of delta functions on our original image geometry and then
run them through Shepard. The new points are now smeared,
we presume by a gaussian, with an effective sigma which
appears to be someone less than one pixel.
SO, MY QUESTION: is "psf" a good task to use for this?
We were thinking of running all hit-pixels on our remapped
image through psf as if the image were a star field with a
very nice seeing. I should add that Shepard imposes "ringing"
and so there may be pixels that have negative intensities as
well. We only have one machine, an IBM, which runs daophot
locally. It runs under UNIX. If this is a good tool to use, the question comes up for
other uses down the line: is there an analogous task that
can run with a RECTANGULAR geometry, such as might be used
to analyze the resolution of emission lines on an echelle
format. I will be here for a couple of hours if you want to call,
or otherwise e-mail is fine. Many thanks. Hope all well there.Cheers -- Myron (301 - 794-1464)