Spectrum of an ice giant

I’ve been getting back into spectroscopy in the last couple of weeks.  I tried to get a few spectra of stars tonight but it was very much a case of dodging clouds and taking limited windows of opportunity!

Just before packing up it occurred to me that the planet Uranus was very high.  Despite imaging through high cloud I managed to get a half decent spectrum:


The spectrum is dominated by various dark bands created by methane absorption in the Uranian atmosphere. The methane mostly absorbs reddish light; this is what gives Uranus the overall blue colour in photographs.

My dispersion for this setup was 7.7 angstroms/pixel.  I hope to improve on this soon.

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