This is an embarrassing post, but I’m going to forge ahead. Time was, we used IRAF and we hated it, but what else was there? Now, there are many choices, lots of them buggy and badly documented, some of them superb.
Say I have a one-dimensional, flux-calibrated, wavelength-calibrated spectrum. (So, all the hard work of calibration is already done.) I want to measure equivalent widths, fluxes, and wavelengths of lines, interactively and then non-interactively. What software packages can people can recommend?