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IC405 - Flaming Star Nebula: Making Stars a Uniform Color and Round

astrophotography
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4 replies to this topic

#1 Alan221B

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Posted 16 December 2018 - 05:12 PM

Hi, 

 

Attached is the result of 22 images stacked (with histogram stretch and image size/bit depth reduced to save space). I did not do post processing beyond this point. Each combined image was 15-minutes and taken from a northern San Diego CA light polluted location.

 

So wondering, how can I get rid of the blue halos/star fringing as well as make the stars round (my deconvolution techniques have undesired side effects - e.g. halos)?

 

Other Details:

Filter - TRIAD (dual narrow band)

Camera - ZWO ASI 294 Color

Binning - none

Gain - 390

Notes:

- Images taken prior to 11:11 PM last night were at 0 degrees C and after that they are -15 C (versus anything in the image file names). 

- House lights on had some impact on image background light pollution.

 

Probably too much to ask about other useful tips for processing this image, but feel free to comment. The main software I have available is SGP, AstroArt, PixInsight, Astra Image, AIP4Win (used for deconvolution), Nebulosity, Anne's Astro Actions, NoiseWare (noise removal) and Photoshop.

 

I read an initial guidelines post but did not see anything on how to post multiple images, so here they are from dropbox. Feel free to correct me if I should do something different.

https://www.dropbox....MShYNtZ3ga?dl=0

 

Thanks,

Alan

Attached Thumbnails

  • IC405 Stacked and Stretched Result.png

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#2 Mert

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Posted 21 December 2018 - 06:23 PM

Did you have tracking problems, stars seem slightly elongated!

I downloaded the frames and processed quick with APP and Pix.

Not sure where something went wrong but there might be something

wrong with the tracking/guiding maybe?? Also the FWHM seemed

a bit high, maybe bad seeing?

I didn't do anything at all with deconvolution or other tools to

improve the image apart from stretching and some curves.

 

I hope you don't mind my try on your frames!

Regards,

Mert

 

 

Attached Thumbnails

  • IC405_flaming_star_APP_streched-Pix-small.jpg

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#3 Alan221B

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Posted 23 December 2018 - 08:22 AM

Hello Mert,

 

Thank you and fantastic! I really like what you did and how it turned out with APP and PI on all accounts (i.e. star roundness, color and in general). I especially like the star color improvement and how some of the faint areas were pulled out. I did some additional color balancing and that seemed to help somewhat, but your processing did a better job. I will look to adding APP to my list of software. The one year rental looks like the way to go for now. I am just starting to use my copy of PI.

 

Yes, you are right. I am using an older LX3 OTA without mirror locks and hence the elongated stars. You mentioned a potential problem with guiding for which I will keep an eye out for other issues other than what I mention here. I plan to try some non-money solutions next including (1) FlexRx with Metaguide to compensate, (2) removing the reducer on my guidescope (as a minor attempt to help this), and (3) seeing what I can do in software processing. Although not ideal, #3 looks interesting as a short term solution especially if I can find something that will address more than elongation but other oddly shaped stars as well. My ultimate solution, I am thinking, is to purchase an EdgeHD scope. 

Cheers,

Alan



#4 terry59

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Posted 23 December 2018 - 09:08 AM

The dark I looked at was unstretched but the light I downloaded was. This looks totally blown out to me

 

I would be shooting far shorter subs

 

Edit....over TWO HUNDRED looks and no help offered.....terrible showing

sigh2.gif

Attached Thumbnails

  • Capture.JPG

Edited by terry59, 23 December 2018 - 09:12 AM.

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#5 Alan221B

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Posted 24 December 2018 - 04:13 PM

Terry,

 

Thanks for the excellent feedback/point! Next time I will look to shorten the exposures or, if the guide/star roundness issues are solved by then, lower the ZWO ASI 294 camera gain from 390 to 120 (i.e. lower to unity gain). Crossing my fingers I will get some good nights during the holidays :). Thanks again! Alan




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