Quote:
Originally Posted by Merlin66
Julian,
Well done mate!
Just a comment - focus on the spectrum (not the zero order) to maximise resolution.
There are some comparison planetary spectra (Titan, Uranus and Neptune) taken with a similar set-up by Torsten Hansen in "Astronomical Spectroscopy for Amateurs", p128
Onwards and Upwards
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Thanks, Ken.
This capture was taken a couple of weeks ago. I've been trying to focus on the spectrum rather than the zero-order, but I've also being working on optimal exposure settings, etc. Part of the issues with this capture are probably sub-optimal focus, but I think it's also affected by pretty average seeing (I was shooting over the roof of my house, and into the sky-glow of Brisbane City, which is only 6 km from my home), and not enough frames to get a really clean stacked image.
Every night that I get outdoors now, I am getting better and better data, but I was pretty excited by the fact that even this clumsy beginner's effort was able to find methane in Neptune's atmosphere.
I've got a copy of "Astronomical Spectroscopy for Amateurs" (a great reference, by the way - highly recommended to any other beginners!) - I'd forgotten about the section on planetary spectra. My extracted spectrum is pretty rough, but it's still quite a good fit with Torsten Hansen's analysis - if I was of a suspicious mind, I'd think that my data had been "fudged to fit"!
