NGC 6543 / Caldwell 6 - The Cat's Eye Nebula

[x6gas]

Well, after months of terrible weather we've had an amazing run of clear skies and lots of superb images posted as a result.

I've been beavering away on a couple of targets shaking down my new Esprit 150 scope.  This has been a bit unusual for me as part of that has involved buying a small lathe and making a custom adapter to couple the SkyWatcher flattener to my Atik gear.  The adapter works really well and I am pleased with the flatness and orthogonality of the field.  However, my filter wheel started behaving erratically and finally gave up the ghost and I think the Esprit represents the limit of what my CEM60 can handle as I've been having some odd guiding behaviour from what has been a very reliable mount.  So acquiring the data for this has been a bit painful...

I've first had a crack at imaging the Cat's Eye planetary nebula in 2014 and have been meaning to get back to it.  For those that have tried it, it's a tricky target; the centre is very, very bright but the outer haloes fairly dim.  I decided to shoot 10 minute subs for the faint stuff but I do wonder whether I should have gone longer...

I've been tinkering and tinkering with the processing and can't quite decide which way to take this now, so thoughts very welcome.

Here is RBG with the OIII blended in at something near its true colour but with the Ha mapped to yellow to bring it out a bit more:

And here is an HOO version but with the outer haloes stretched a little less:

Maybe I've left the background a little too light?

I used 30s subs for the core (I captured 180s subs too but didn't use them) and blended it in unstretched.  I was quite pleased with the structure on show given that my seeing is always pretty poor.  Just for fun, here's how my core compares to the composite HST visible and Chandra X-ray Observatory image.

Kit: Mount: iOptron CEM 60EC; Scope: SkyWatcher Esprit 150; Imaging: Atik 460ex; Atik EFW2 (and then a new EFW2.2 half way through); Atik OAG, Astrodon filters; Guiding: QHY 5LII and PHD2

Data: OIII 60 x 600s & 20 x 30s; Ha 60 x 600s & 20 x 30s; RGB 20 x180s per channel.  All binned 1x1.  Total integration time 23hrs 20m.

Thanks for looking and clear skies.

Ian

Edited April 26, 2020 by x6gas
missed scope off of kit list

[MarkAR]

Lovely images, looks like a really difficult target.

[fireballxl5]

Great image and very nice colours. The background looks fine on my tablet. 

This gives me something to aim as I'm currently working on this target with my 150mm refractor. From my experience with the Owl nebula, I started with some lum data, 600s, 60s and 20s subs, followed by similar for OIII. I plan to get some Ha and maybe RGB for the stars eventually.

CS, Andy

 

[DaveS]

I had a look at this myself a couple of months back and I too found getting the brightness tamed to be a real headache, even with DDP. But TBH it was only look-see and will have to wait for the ODK12.

[assouptro]

Cracking image Ian 

I am impressed with the detail you have achieved 

thanks for sharing

Bryan

[x6gas]

Thanks for the likes and comments everyone - much appreciated.

19 hours ago, MarkAR said:

Lovely images, looks like a really difficult target.

Thanks Mark, much appreciated.  The 10 minute subs needed quite a stretch so I had to balance sharpening with noise reduction (as ever).  I know there is some blue in the background surrounding the PN in the first image but I left a little glow in deliberately as it made the transition smoother and I quite liked it at the time... I'm less sure now! 

12 hours ago, fireballxl5 said:

Great image and very nice colours. The background looks fine on my tablet. 

This gives me something to aim as I'm currently working on this target with my 150mm refractor. From my experience with the Owl nebula, I started with some lum data, 600s, 60s and 20s subs, followed by similar for OIII. I plan to get some Ha and maybe RGB for the stars eventually.

CS, Andy

 

Thanks Andy.  I will process the 180s data just to see, but a quick look seemed to suggest there was nothing in those subs that helped the core.  The RGB stars were easy and I just masked the nebula through the star field manually.

11 hours ago, DaveS said:

I had a look at this myself a couple of months back and I too found getting the brightness tamed to be a real headache, even with DDP. But TBH it was only look-see and will have to wait for the ODK12.

When I first attempted a rough process (with about half the data) I found blending in the core a real pain but in this run through it seemed to go OK (which is why I ended up not using the 3 minute subs), though I did sacrifice some definition.  Thanks again Dave.

11 hours ago, assouptro said:

Cracking image Ian 

I am impressed with the detail you have achieved 

thanks for sharing

Bryan

Thanks Bryan.  The new scope certainly seems to have potential, though as I say guiding was more of a challenge.  It's also the first time I've tried dithering - never seen the point before as I could clean up the few hot pixels my camera has with darks and pixel correction in AstroArt or PixInsight but I read a thought-provoking post by @vlaiv and decided I needed to introduce it into my capture process.