Using Startools with spectra?

[Gasman]

Hi Ivo
I`ve been using a Star Analyser diffraction grating to do some spectroscopy. The Star Analyser gives you a first order spectrum at a fixed distance from the star see attached shot of one I took a while back of Vega (under not ideal conditions!). (Fits files are not a permitted upload to Photobucket hence the jpg!)
http://s535.beta.photobucket.com/user/5 ... sort=3&o=8
I have been trying to use Startools to tease out the faint dark spectral lines but not having much success and wondered if you could suggest a workflow to do this with Startools or if indeed Startools is able to do this at all please?
Thanks
Steve

[admin]

Hi Ivo
I`ve been using a Star Analyser diffraction grating to do some spectroscopy. The Star Analyser gives you a first order spectrum at a fixed distance from the star see attached shot of one I took a while back of Vega (under not ideal conditions!). (Fits files are not a permitted upload to Photobucket hence the jpg!)
http://s535.beta.photobucket.com/user/5 ... sort=3&o=8
I have been trying to use Startools to tease out the faint dark spectral lines but not having much success and wondered if you could suggest a workflow to do this with Startools or if indeed Startools is able to do this at all please?
Thanks
Steve

Hi Steve,

That's an interesting way of using post-processing software!
Would you be able to tell me a bit more about what aspects in the data you are looking for to bring out? Any 'before and afters' (images) you could point me to, to help me understand what goal you are trying to achieve? Raw (unprocessed) data to play with would also help tremendously.

Thanks!

[Gasman]

Great Ivo thanks
This is a cropped jpg of a fits I did of Uranus last year with just the spectrum showing -
http://s535.beta.photobucket.com/user/5 ... sort=3&o=0

and this screen grab is what the spectrum shows when run through some spectrum software, one I mainly use is an excellent free one called BASS (stands for Basic Astronomical Spectroscopy Software) . The dark lines (troughs in the graph) or light lines (Peaks in the graph) are the ones indicating the various molecules at specific wavelengths and its this light/dark difference that the software plots in graph form and what I`m trying to bring out in the shots. You can see the raw spectra above the graph.

http://s535.beta.photobucket.com/user/5 ... sort=3&o=5

I have been using Photoshop CS2 so far but the tweaking of fits files (I used bmp`s with my last camera and now have an Atik ccd) is proving a bit harder to do. I`m sure the detail is there but I haven`t cracked it yet.
This is a better one of PCyg showing a H alpha emission line
http://s535.beta.photobucket.com/user/5 ... sort=3&o=0
Hope that describes what I`m trying to do. I can send you a fits of these if you want?
Best
Steve

[admin]

A TIFF or FITS file would be fantastic Steve.

[Gasman]

Thanks for that Ivo, hope I`ve done this right as I`ve linked a fits of PCyg via Dropbox
https://www.dropbox.com/s/y8s7tnlc3zn8yum/PCyg.fit?m

Regards
Steve

[Gasman]

Well after playing with that PCyg fits in Startools it looks like I might be getting somewhere but can`t save it will have to get me a licence
Steve

[admin]

Ok, I had a look.
The module that I can see make a difference is the deconvolution module.
When you use it, make sure you put it in Lunar/Planetary mode, so it doesn't clip highlights.
To be able to use it at all, you'll have to indicate that the data is still linear when loading, then launch the Develop module and just click 'keep'. This should satisfy StarTools when it is checking if you will actually be able to see the effects of deconvolution.
There is no benefit in stretching anything, nor can I see any benefits in any HDR manipulation etc.
What sort of reading does this give you?

PCyg.jpg (2.62 KiB) Viewed 11595 times

[admin]

Well after playing with that PCyg fits in Startools it looks like I might be getting somewhere but can`t save it will have to get me a licence
Steve

There's always taking a screenshot...

[admin]

There is no benefit in stretching anything

Actually, the AutoDev module might be rather useful if you specify a Region Of Interest (click & drag along the central line). It'll do its best to allocate dynamic range in such a way that the peaks stand out as much as possible.You may have to rotate the image so that the line is perfectly horizontal first.
Afterwards, to create a linear reading again, do an 'inverse' gamma correct using the Develop module ('stretch-as-is', Gamma around 0.45).
Could be fun!

[Gasman]

Nice one Ivo.
Just cropped a screen grab of yours and come up with this

Looks like its a goer

Cheers
Steve
Ps Can`t seem to show the image on the forum?? so had to do a link
http://s535.beta.photobucket.com/user/5 ... sort=3&o=0