I’m trying to orientate myself. To make things easier, could you say (a) whether shorter wavelengths are to the left or the right of the image as shown here and (b) are the lighter colours bright emission lines (i.e. it’s a positive image) or dark absorption lines on a negative continuum?
I’m almost certain that its the first in case (b) but it would be good to have it from the horse’s mouth as it were.