iraf.net

hello...
Iam Martha Bello, and i am a master student at INAOE, i have a question about
the task GAUSS. The task convolves a spectrum with a gaussian, in the parameters
that this task need are the sigma of the the gaussian but in pixels, how i do
this?, that means that i need convolve my spectrum with a gaussian with a sigama
in km/sec, how can i do for convert this sigma in pixels?.... Regards

If what you're trying to do is rotationally broaden the spectrum, the use the forum search to look for 'rotbroad'. This will bring up an old script which does just that. Note however that you may need to tweak the script a bit for your purpose.Otherwise, in the RV package the velocity dispersion is calculated as the WPC in log space (i.e. (log(W(n+1))-log(W(n)) where 'W(n)' is the wavelength at pixel 'n' times C times ln(10).
Note also that in SPLOT there is a ":units" command that will let you plot a spectrum in km/s units.-Mike