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Line profile creation with RSpec, VSpec and Fitswork

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#26 mwr

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Posted 24 December 2019 - 05:50 AM


 

Obviously I have a problem with the RGB to luminance conversion in RSpec already at the level of the raw file.

Tom Field, the developper of RSpec, has been following this thread and he has analysed the phenomenon in depth after I had send him the raw file. First of all he has offered me a free download of the latest version of RSpec (I was using a quite old version): Great customer service! Thanks Tom!

The rotation of a RGB image with a low signal to noise ratio can also contribute to this phenomenon and Tom did send me an insightful video on this topic.

 

Obviously the use of a DSLR camera for spectroscopy is ok for the first steps (low price and a large sensor; the Canon 450 Da I'm employing is a used one that I bought for 100 USD and did modify myself) but for diving deeper into the topic I have to get a cooled CCD (though the prices for CCD's with an APS-C sized sensor really knocked me out....)


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#27 Organic Astrochemist

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Posted 24 December 2019 - 02:09 PM

That’s where CMOS cameras make sense for some people. You get what you pay for, of course, and for great resolution and sensitivity, spending over two thousand dollars for a CCD can get you that. The ASI1600 or ASI183 are less expensive CMOS options (I think the latter is preferred). Then there are the IMX178 and IMX290 based cooled cameras that only cost $500-$600 but aren’t really big enough to max out the resolution and still see the zero order spectrum. I have greatly enjoyed both of these. As CMOS cameras replace CCD cameras it may be possible to buy used CCD for less. The lower noise of the CMOS cameras place less demands on the guiding/mount (see my grab and go system).

I highly recommend that people use whatever they have to start spectroscopy.

I think that what you have shown, for example with your excellent spectrum of IC2003, is that by choosing your targets wisely one can learn a lot about spectroscopy with modest equipment.

Frohe Weihnachten.

Edited by Organic Astrochemist, 24 December 2019 - 02:33 PM.

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