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You should first try flipping the X axis, and making sure that you still can’t get a match. When you open a GMOS fits exposure, you usually have the longer wavelengths on the left side of the image, which means that you need to flip the X axis to visually recognize a match to the reference CuAr images.September 13, 2016 at 12:57 am in reply to: Discussion Topic: Correcting for Slit Tilt in GMOS Spectra #1365
I use a method similar to what you described, but with several small tweaks to make the code robust. You can find the routine that I’m using, called “align_trace3.pro” (it’s in IDL) in the Red Flamingos pipeline for Flamingos 2 here:
(look in /pro/general_pro/)
It is really the same principle with GMOS, I’ve been using the same routine to reduce GMOS data.September 6, 2016 at 4:51 am in reply to: Removing H lines from the telluric standard spectrum #1354
Most of the time I use the xtellcor_general.pro IDL routine that is available as part of the spextool reduction package, which you can download here: http://irtfweb.ifa.hawaii.edu/~cushing/spextool.html
I’m not sure exactly what functional form is used to model the H lines, but I believe that it is a Lorentz profile convolved with a Gaussian and a rotation Kernel (if you enter a value for v sin i) – you typically use the deepest H line to build a model for the kernel, and then you can adjust the relative strength of each line as a subsequent step to make sure that they fit your observed telluric well.
The only downside to using xtellcor_general.pro is that you need to have IDL and to feed it spectra that are formatted in a special way – the header must contain several key entries. If you would like to try it, you will need to open the routine writespec_ps.pro (also part of the spextool package) and see how they output the data.
If you are using Flamingos II data specifically, I will soon be posting a complete IDL pipeline to reduce F II data on this forum, and it will makes use of xtellcor_general.pro, so you will see exactly how the data needs to be formatted.