Well, it's been a fun New Year, with the arrival of a Star Analyser 100, to go with Ken's book that has sat on our shelves for a little while, and a trial copy of RSpec! I was given the Star Analyser with the express objective of taking a spectrum of Uranus by
my physicist wife, whose PhD topic was studying high pressure methane and ice compounds that you find in the outer Solar System (yes, ice in space
).
I got a little nervous with Uranus heading to the horizon and the weather not being co-operative, but eventually got a break on 8th January - bingo! I took a sequence of 97 14-second exposures of Uranus, and was pretty happy with the individual spectra. But then I tried a strategy of rotating and cropping the images in Digital Photo Professional, aligning the spectra with the planetary program PIPP (I wasn't guiding, and so each exposure wasn't quite in the same place), then using the AVI in RSpec to stack the images - the results are below and I'm pretty happy with them. I took a shorter sequence of 19 x 19-second exposures of a reference G2V star for the calibration, ISO-800. Though my calibration may be a tad off, there are very clearly the methane bands in Uranus, and perhaps a couple of other absorption features near 5100 and 5200 angstroms - I've tasked my wife with identifying them...
Fun to do some science again!