Question on processing the Cat's Eye nebula (NGC 6543)

Questions and answers about processing in StarTools and how to accomplish certain tasks.
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Moonstruck
Posts: 10
Joined: Mon May 16, 2022 10:43 am

Question on processing the Cat's Eye nebula (NGC 6543)

Post by Moonstruck »

Hello,
I recently processed the Cat's Eye nebula with Startools, and have a couple questions. I am still new to using Startools, and am in the process of learning the program. First, there is no detail in the center of the nebula- it just looks like a small bright dot with no distinguishing features. Second, there is a faint veil that is supposed to surround the eye, but I couldn't get it to stand out more than what you see in my processed picture. Any suggestions on how to get these features to show up? I went through the Startools processing screens systematically, but can't figure out what I did wrong. Or, is it a focus issue? I used a bahtinov mask, and focused on one of my alignment stars, but that star wasn't in the vicinity of my target.

I included a link to the raw stack (about 4 hrs of 60-sec exposures, along with 20 flats, 20 darks and 20 dark flats). I also included a link to my processed image. I used a Skywatcher Esprit 100 telescope (unguided), EQ6-R-Pro mount, and ZWO asi 294MC Pro color camera. I used Sharpcap Pro for capture, with the gain set to about 120.

Raw stack: https://drive.google.com/file/d/1tfRAPv ... sp=sharing

Processed image: https://drive.google.com/file/d/1y78efI ... sp=sharing

Any advice you can provide will be appreciated.

Thanks!
almcl
Posts: 232
Joined: Wed Jan 21, 2015 7:15 pm
Location: Shropshire. UK

Re: Question on processing the Cat's Eye nebula (NGC 6543)

Post by almcl »

Thanks for sharing the data.

I had a quick play and my first go is very similar to yours:
NGC6543.jpg
NGC6543.jpg (77.46 KiB) Viewed 392 times
So I tried again, with a more aggressive stretch at the 2nd Autodev and got more detail in the nebula at the expense of the stars and background:
NGC6543(b).jpg
NGC6543(b).jpg (156.69 KiB) Viewed 392 times
I think the placement of the Region of interest is probably key to getting a good compromise.

If either is of interest, I can share the log file?
Skywatcher 190MN, ASI 2600 or astro modded Canon 700d, guided by OAG, ASI120, PHD2
Moonstruck
Posts: 10
Joined: Mon May 16, 2022 10:43 am

Re: Question on processing the Cat's Eye nebula (NGC 6543)

Post by Moonstruck »

almcl-thanks. I have seen pictures of this nebula from others with very good detail of the center, and a highly prominent veil surrounding it, but suspect they had much bigger scopes and/or a lot more exposure time than I did. I also tried stretching the curve more, as you did, but the surrounding stars were much too bright/colorful. I appreciate your help. Thanks for spending the time. Maybe next time I'll try for 10 hrs or more exposure to see if that makes a difference.
Mike in Rancho
Posts: 541
Joined: Sun Jun 20, 2021 10:05 pm
Location: Alta Loma, CA

Re: Question on processing the Cat's Eye nebula (NGC 6543)

Post by Mike in Rancho »

Not an easy target, but small and faint PN's tend not to be, I think.

More time would indeed probably help. Also, duoband filters are often perfect for red and blue PN's. Moreover, longer reach and perhaps shorter exposures might improve the results.

I could only do so much with the inner core, it's just bright, even throwing strong HDR at it. Particularly so when also trying to stretch out the faint outer structure.

But those are probably really fine details as well, and I'm not sure your imaging scale (somewhere around 1.7"?) supports getting in that deep, especially without guiding.

Still, pretty cool that you did manage to capture a good bit of that outer ringing it seems. Before denoise I did hit it with a couple clicks of Filter/Conservative Nudge on the blue just to try to pop it a little bit more. I probably should have on that tiny bit of red showing too, but didn't see it until too late. :lol:

moonstruck CENeb ST8 2B.jpg
moonstruck CENeb ST8 2B.jpg (475.05 KiB) Viewed 387 times
Moonstruck
Posts: 10
Joined: Mon May 16, 2022 10:43 am

Re: Question on processing the Cat's Eye nebula (NGC 6543)

Post by Moonstruck »

Thanks Mike. You probably remember me from CN. Once again, I appreciate your input! I am getting up to speed quickly with Startools and as you can see, I have started posting questions on this forum. The Cat's Eye nebula has been my most challenging processing target thus far. I'm still using Sharpcap, and am getting better at it as well.

John
fmeireso
Posts: 132
Joined: Mon Sep 28, 2020 8:46 pm
Location: Belgium

Re: Question on processing the Cat's Eye nebula (NGC 6543)

Post by fmeireso »

Diffucult target.
But i think you did a good job.
I stretched it pretty far, blowing up a bit the surrounding stars. I made it go to the blue, yours tends to go to the green.
Still an intriguing object
Catseye.jpg
Catseye.jpg (69.85 KiB) Viewed 244 times
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