Data Reduction Frequently Asked Questions

How can I correct telluric absorption lines in the Reflex science end products?

There are basically 2 ways:

  1. You select the zones to correct, you normalize both the science and the std star spectra to the continuum, then you divide one by the other. This should remove the telluric lines. Be careful, depending on the telluric std star, you may have stellar lines as well in the std spectrum.
  2. You do a fit of the lines on the telluric std star spectrum with an atmosphere model, this gives you a first guess that you will apply on the science spectrum and on this one you will adjust the residuals to remove again more properly the telluric lines.

A software tool to  fit and correct the telluric lines directly in your science spectra without the needs of using an observed telluric standard star is available at