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Stacking and Data Capture: Spectroscopy

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#1 Xshovelfighter

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Posted 14 April 2019 - 02:39 PM

Hi all, 

 

I dabbled with the Star Analyzer 100 and RSpec a few years back but then got sidetracked taking "pretty" pictures and the astrophotography end of things.  I am now ready to get back into things, which actually works out now that I have a better setup and equipment to do spectroscopy as well.  My question is regarding data collection.  My concern is with stacking the subframes that I collect. Deep Sky Stacker (DSS) is great but when I am collecting spectra of brighter stars and have very short exposures, no other stars are really going to show up and DSS obviously needs more than 1 - 2 stars.  This wouldn't be a cocnern when imaging dimmer stars, as there would be several stars brighter than the target star.  Any suggestions for this?

 

My next question is along the same line.  It looks like it is possible to do my data collection in RSpec itself...?  I fiddled with my camera and the software during the daytime today and really like the live play and image averaging/stacking option.  My question is how to take this live feed and save it to a single image for use in the RSpec analysis?  Further, assuming this is a pretty easy thing to do, is this a good method that would yield quality results as compared with a third party software?  I really like Sequence Generator Pro for data collection but if RSpec could handle data collection and also cover the stacking end of things as well.

 

Thanks for any insight or help with this!  



#2 robin_astro

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Posted 14 April 2019 - 04:38 PM

You could check with Tom Field but I don't think RSpec can align and stack on the fly currently so my advice would be to use RSpec to set everything up and get best focus. Then take a series of frames and align and stack them (either on the fly or off line using your favourite software) Using the zero order as the reference and choosing the sharpest as for planetary imaging  to produce a aligned and stacked composite image which you can then pass back to RSpec or other spectrum processing software. (You only need one star to align on as field rotation is not a problem because the spectrum is always in the same direction relative to the camera.)

 

You can see the outline of the similar procedure I use here but using the capture software provided with my camera and ISIS software for the processing

http://www.threehill.../spectra_42.htm

 

Cheers

Robin  


Edited by robin_astro, 14 April 2019 - 04:50 PM.


#3 Xshovelfighter

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Posted 15 April 2019 - 05:47 PM

Robin,

 

Thank you very much for the help!  Which softwares allow for stacking with only 1 or very few stars?  This is my main sticking point as I don't know how to produce a stacked image when there are only 1 or 2 stars.  DSS can't do this as far as I know.  Guess I may have to learn a new software?

 

Thanks again!



#4 robin_astro

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Posted 15 April 2019 - 08:17 PM

I use either K3CCDTools (which I have used since I first started with webcam imaging over 15 years ago but it is rather old now and there might be better programs around) or ISIS which is a very powerful program for spectroscopy and also has an alignment tool but ISIS can be a bit a bit tricky to get used to.  Any planetary imaging software should be able to do it though, provided you can manually select a single point or small region containing the zero order to align on.

 

Cheers

Robin


Edited by robin_astro, 15 April 2019 - 08:18 PM.



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