After a long hiatus, I'm starting to do a little spectroscopy again.

The challenge -- a decidedly first-world challenge -- is that about a year ago I sent my whole rig down to SkyPi in New Mexico and have been operating it remotely there ever since. (SkyPi is great, by the way, as are the skies.) I made a few attempts to use my diffraction grating, but found it really hard to focus, etc., over RemotePC. The image quality is not great. So after a frustrating night or two, I gave up and took some pretty pictures instead.

With the appearance of the relatively bright supernova SN2022hrs near (visually) M60, my interest came back. But again I was frustrated by the clumsiness of trying to focus the spectrum, etc., over a slow, grainy remote connection. So, I decided it was time to conquer the madness with some method. I found a nice bright star and spent an evening getting it focused with a luminance filter and then making a series of exposures with the diffraction grating, about 100 focuser steps further in with each exposure, downloaded it all and determined the spectrum focuses at about 2000 steps in from the luminance filter's focus point. With further trial and error, I figured out that to properly position the spectrum, I needed to shift the center point of the frame about 1' 30" to the west of the star. Getting the brightness right -- bright enough to get good lines without saturating any pixels in the spectrum -- is still an iterative process but I'm hoping to make it more systematic as well.

Anyway, now that I have a process, it's gotten a lot easier to get spectrums again.

This is Unukalhai, a K-class star in Serpens. The hydrogen lines are muted, but some heavier metal lines start to appear in the class. The overall color is clearly weighted towards the red end of the spectrum as well. The blue line is the reference Pickels spectrum for K2 iii stars.