reducing spectra with IRAF

[soroush71]

hi everybody.

I started reducing spectra with IRAF and i have already read A user's guide to reducing slit spectra with IRAF by Phil Massey but i encountered some misunderstanding:

1)how to subtract background from spectrum

2)I followed flux calibration step by step but encountered an error: no degrees of freedom

3)how to make a .txt file from an reduced spectra to know intensity of each wavelength step (e.g. intensity per 2 angstrom)

I will appreciate giving any information you have to help my problems.any exprience you had with IRAF could be helpful.

I also need some .fit images to be sure that there is no problem with my own images.

thnaks a lot for reading my post and helping.

best regards

soroosh.

[Merlin66]

Soroosh,

Welcome on board!

Can I ask why you selected IRAF to use?

IMHO it's certainly not the easiest program to come to terms with! There are more (professional) users in the US.

Have you considered VSpec or ISIS?

Which spectroscope, telescope and camera are you using?

[Ben Ritchie]

I use IRAF all the time for post-pipeline calibration (then again, i'm old-fashioned enough to use DIPSO too), although I don't tend to use it to do the whole reduction from raws unless I have doubts about the pipeline.

I'd agree with Merlin66 though that it's a steep learning curve and there are better choices out there, I only use it through habit as onedspec is pretty much hardwired into my brain by now.