Improving the colors in the Veil

Questions and answers about processing in StarTools and how to accomplish certain tasks.
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sandconp
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Joined: Tue Dec 03, 2019 6:59 pm

Improving the colors in the Veil

Post by sandconp »

I was wondering how I could bring out more color in the Western Veil Image using Star Tools. I am pretty happy with my results but I would like to improve on the color of the wispy tail which is harder to see. When I try to lighten up the image that helps but then it brings out more stars which I don't want to see.

I have my fits file in Dropbox and my final image if you want to take a crack at it.

https://www.dropbox.com/s/2obh2b91zcdu5 ... .JPEG?dl=0

https://www.dropbox.com/s/x5phtmtshpn44 ... .fits?dl=0
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admin
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Re: Improving the colors in the Veil

Post by admin »

Hi,

Normally, this would be a perfect case for the Entropy module and/or Sharp modules.

However, I'm a bit worried looking at your dataset - it appears stretched, as the nebulosity is readily visible upon first open.
It may also be that you used an extremely high exposure time for each frame (this blows stars out amongst other things)

How did you stack and pre-process this? Was a light pollution filter used as well?
Ivo Jager
StarTools creator and astronomy enthusiast
sandconp
Posts: 20
Joined: Tue Dec 03, 2019 6:59 pm

Re: Improving the colors in the Veil

Post by sandconp »

Hi Ivo,

I use Sharpcap Pro to perform live stacking so when I am finished, I have one fits file. I always use a light pollution filter on my Hyperstar Lens. My exposure on this image is 3 minute exposures for a total of 45 minutes using gain of 225.

I did not stretch this image it's the native stacked fits image.
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admin
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Re: Improving the colors in the Veil

Post by admin »

Thank you.

Live stacking is generally not recommended, as an off-line stacker can do a far better job when it has all data available to it (not just as it comes in). Using SharpCap, try acquiring RAW files and saving them (rather than stacking them), then stack them in, say DSS, where you can use more accurate and sophisticated outlier rejection algorithms such as kappa-sigma rejection (which necessitate having all frames at hand to perform the calculations).

Try finding a more suitable gain or - if you cannot - exposure time, as your stars are all overexposing right now. Normally, all but the very brightest stars have neat stellar profiles that taper off. Only the very brightest stars will/should show burnt-out cores. E.g, right now, you are sub-optimally using your sensor's dynamic range.

The light pollution filter explains the blue bias in your dataset, thank you.
Ivo Jager
StarTools creator and astronomy enthusiast
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