NGC 6543, Cat's Eye nebula

[iansmith]

Hello,

This is my attempt at imaging NGC 6543, also known as the Cats Eye nebula. This has a very nice bright core and a much fainter, but very extensive, outer halo which makes for something of an imaging and processing challenge.

This image was taken over a several nights between the 9th August 2017 and 21st September 2017. Taken with my Edge 11/Atik 414EX combination at F/10, it is a bi colour image of Ha and OIII. For the outer halo I took 18 x 1200s Ha exposures and 15 x 1200s OIII exposures all at 1x1 binning. I lost a few of the OIII ones due to clouds appearing half way through the exposures. For the inner core it was 12 x 300s Ha exposures and 12 x 300s O3 exposures, again at 1x1 binning. Data was captured using SGP.

Everything is mounted on a Mesu 200, guided via ONAG, an ASI178MM camera and PHD2.

I used Pixinsight to preprocess the files to give me 4 images: Ha halo. Ha core, OIII halo and OIII core. I then used Pixinsight to do all the post processing of each of the 4 images before combining the Ha halo and Ha core to get a single Ha image and likewise with the OIII images to get a single OIII image. These two where then combined to give an RGB image by mixing the Ha and OIII as: Red 100% Ha; Green 50% Ha, 50% OIII; Blue 100% OIII.

The nebulosity was treated separately from the stars, so they are a bi colour combination of the 1200s exposures in Ha and OIII and combined using the same recipe as the nebula.

So after all the boring technical stuff, here's the final image:

 

I hope you like it, this is only my forth image so I've still plenty to learn.

Cheers, Ian

[Jannis]

Really nice!

I've tried multiple times to capture this one myself, but all failed attempts. The core is too small to capture any details, and the surroundings are too faint to capture at all. If i could get something even remotely close to what you have i'd be really happy!

[Hayduke27]

I just saw spotted this object for my first time this morning.  Nice image!!

[iansmith]

8 hours ago, Jannis said:

Really nice!

I've tried multiple times to capture this one myself, but all failed attempts. The core is too small to capture any details, and the surroundings are too faint to capture at all. If i could get something even remotely close to what you have i'd be really happy!

Thanks Jannis.

[iansmith]

7 hours ago, Hayduke27 said:

I just saw spotted this object for my first time this morning.  Nice image!!

Thanks Hayduke27.

[Owmuchonomy]

That is some dedication especially at that focal length. Nice to see something more unusual in an imaging post.

[iansmith]

22 minutes ago, Owmuchonomy said:

That is some dedication especially at that focal length. Nice to see something more unusual in an imaging post.

Thanks Owmuchonomy. 

[Scooot]

An amazing image. What a great result for all your effort. I found it very interesting reading how you captured and processed it.

[cfpendock]

That is a very impressive image. I am interested in your choice of not binning.  With my C11 I always bin at least 2x2 on the basis that the seeing here is rarely better than 2 arc secs, when my camera gives me around 0.5 arc sec/pixel resolution - similar to yours, I think.  So I tell myself that I can save time by binning.  At the same time, my stars, although not particularly "clean" (I think this is to do with long FL), are not "blocky".

Chris

 

 

[iansmith]

1 hour ago, Scooot said:

An amazing image. What a great result for all your effort. I found it very interesting reading how you captured and processed it.

Thank you Scooot. I'm glad you found the information of use, I wasn't sure if people would be interested or not.

Cheers, Ian

[iansmith]

44 minutes ago, cfpendock said:

That is a very impressive image. I am interested in your choice of not binning.  With my C11 I always bin at least 2x2 on the basis that the seeing here is rarely better than 2 arc secs, when my camera gives me around 0.5 arc sec/pixel resolution - similar to yours, I think.  So I tell myself that I can save time by binning.  At the same time, my stars, although not particularly "clean" (I think this is to do with long FL), are not "blocky".

Chris

 

 

Thanks cfpendock. With regards to binning,  as you say my scope/camera combination gives ~0.5" per pixel. My seeing conditions, which are typically similar to yours, would suggest that 2x2 would work but I have never been very happy with the results when I've tried it.

On the Cloudy Nights imaging forums there is some suggestion that you're better off sampling at x3 or x4 to get the best final resolution for an image. Whether that's true or not, I'm not sure. All we can really do is experiment with what gear we have and see what works for a given setup. It would be nice if we had a few more clear nights so we could experiment and collect data!

Cheers, Ian