Backyard Spectroscopy

[Heian (Mark)]

Hi all,
a forum member recently asked about doing some simple spectroscopy. I have been using this piece of gear:
http://www.patonhawksley.co.uk/staranalyser.html

together with this piece of software:
http://www.astrosurf.com/vdesnoux/index.html

The image of Betelgeuse below was taken with a Canon 350D, 135mm f4 lens + 2x teleconverter, 6 secs exposure with a star analyser. Processing the spectra shows molecular bands, TiO, and other various other ionised metals, which is a function of the temp ~3500 Kelvin. A different slant on why stars are the colours they are...

cheers
Mark

[renormalised (Carl)]

Very interesting.....you should be able to expand that 1st order spectrum you have there so you can read it a lot easier. You've got several very strong TiO bands there.

[sheeny (Al)]

Thanks for posting. I had seen the staranalyser before and wondered if they were that practical. Very interesting! I'd like to see more.

Al.

[iceman (Mike)]

Nice work Mark, very interesting indeed.

[Heian (Mark)]

Thanks for the comments guys

renormalised: there are limits on the resolution achievable out of this simple setup. The addition of a slit in the light path, increasing the lines/mm in the grating, increasing the distance from grating to ccd will give some improvement but you reach the limit pretty quickly. On Christian Buil's website, http://astrosurf.com/buil/index.htm there are some mathematical proofs on how accurate you can get with a star analyser type filter.

Long exposure shots were beyond me, so I went for something that seemed, at the time, a bit easier. Now I know different...

Mark