No, I didn’t tick that box. Here is the new improved lamp spectrum which looks accurate. I noticed that the intensity of the lines that ISIS uses for calibration are much weaker than those above 7000 A. Perhaps I should not worry about saturating those brighter lines and try using a longer exposure in order to make the ones used by ISIS brighter.
What do you think is the way forward now? I was hoping to submit spectra to our database. Should I put a comment in the FITs header about the calibration method and its (?) inherent problems, ie mixed method with accuracy upto H beta, 3A blueshift near H alpha.
What would be the best way to calibrate now? Would it depend on the nature of the target?