A strong green auroral line in the ALPY 200 spectra tonight at 20:00 UT. The left of the two strong lines, matching the local NaD line (right) for intensity, even with the target due south. (The very strong “line” on the far left is the zero order slit image)
The target is a follow up of my latest supernova classification sn2017htb (1a 91t-like)
North West Cumbria. Clear skies are like hen’s teeth around here and once again have coincided with near full moon 🙁
I did not notice any aurora visually, though there was a photo on the local weather showing it low in the north. The spectrograph is very sensitive to this line though which is always present at a background level even when there is no aurora.