I was very impressed with this G-Band solar image published on RG by Dr Muller:
https://www.researchgate.net/figure/A-sunspot-observed-in-the-G-band-l-4305-05-nm-with-the-Swedish-1-m-Solar_fig1_29756655
I would like to know the desired spectral characteristics of such a filter like the FWHL and OD blocking each side of the G-Band. If anyone can help I'd really appreciate it.
Thank you