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Old 21-05-2015, 08:40 AM
robin_astro
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robin_astro is offline
 
Join Date: Jun 2009
Location: UK
Posts: 73
Hi Alan,

The spectra running in the opposite direction are the -1 orders. The Star Analyser produces spectra either side of the star image (The zero order). The +1 order on the right of the star is by far the brightest and the one you want but there is also a faint "ghost" spectrum to the left of the star image. The Star Analyser instruction manual has more information on this.
http://www.patonhawksley.co.uk/resources.html

You can see the zero order and +1, -1 spectra in Eta Car in your image, which I have marked (attached) I have also marked WR24 and WR22 and the red emission lines in them.



Cheers
Robin
www.threehillsobservatory.co.uk
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