NGC 6543 "The Cat's Eye Nebula." A H_O_OH image (Pat Rodgers)

NGC 6543 "The Cat's Eye Nebula." A H_O_OH image

After seeing an image on the big wall by Carl Weber where he was having trouble controlling the easily blown core in the Cat's Eye. I had a another go at my 2016 data.

The usual basic pre-processing, after which I combine the stacks into a H_O_OH coloured image.

I ran off three extra clones which are stretched at different iterations using Masked Stretch.

I did a; 100,200,300, and a 500 for the four clones.

On my images i ran the HDR Multiscale Transform; with 4 layers, Median Transform checked and both lightness boxes checked. Other peoples images will need different settings of course.

These are put into pixelmath using the formula in image B:

Final
Original
B
C
D

B

Description: Here's the pixelmath formula for blending the four different stretches together. It's from David Ault's star removal tutorial where he makes one star map from several, which have different star sizes in them, thus covering every star in an image.
My four clones are added into the brackets separated by a comma. You just swap whatever you call your own images.
Hey presto an under stretched image with the core intact with the details preserved. Ready for extra processing.

The result is image A:

Uploaded: ...

C

Description: In a reply to Gary I thought this should work on globular clusters too. So gave it a try.
C: Masked stretched iterations of; 100,200,400,600 and 800. I altered the noise value from the default 0.125 down to 0.1 this keeps my awful background a tad darker.
The change between the 100 and 600 isn't drastic but develops the outer stars in a subtle manner. The difference between 600 and 800 wasn't adding anything to my eye. I would think a 100 and 500 iteration blend would offer a similar end result.

Uploaded: ...

D

Description: D: The final M13 blend. Denoised with a little saturation and an extracted lum added.

Uploaded: ...

Fast Newtonians
UK Astro-Imaging

	Distinct awarded users	Total awarded images
Image of the day
Top picks
Top pick nominations

	Image of the day	Top pick	Top pick nominations	Total submitted
Deep sky
Solar system
Extremely wide field
Star trails
Northern lights
Noctilucent clouds
Landscape

	Image of the day	Top pick	Top pick nominations	Total submitted
Backyard
Traveller
Own remote observatory
Amateur hosting facility
Public amaeteur data
Professional, scientific grade data
Mix of multiple sources
Other
Unknown

Submitted The date and time when you submitted this image for IOTD/TP consideration.	...
Views by Submitters (available since September 19th, 2023) Every image is assigned to 50% of available Submitters. In the event that at least 80% of them don't view the image before its time in the IOTD/TP process expires, it's assigned to the other 50% of Submitters and the process begins anew.
Promotions by Submitters When 3 distinct Submitters promote the image, it moves on to the next stage of the process: evaluation for Top Pick status. This requirement, in addition to anonymization of images and distribution to only a subset of them, prevents biases and ensures that the best images are selected.
Promotions by Reviewers When 3 distinct Reviewers promote the image, it moves on to the next stage of the process: evaluation for IOTD status.
Early dismissal Staff members have a lot of images to inspect on a daily basis, and they can dismiss images if they believe they don't meet the requirements for IOTD/TP selection. If an image is dismissed 5 times, it's removed from the process. This streamlines the process and ensures that any bias present in promotions could be overruled by other staff members.

Status	Advanced success
Started	...
Astrometry.net job	3907754
PixInsight job	QQ10GZ80EE6Z0B0RXA6ZFIFXD8L0VD4E
PixInsight queue size	n/a
PixInsight stage	n/a

RA (center)	17h58m34s.32
RA (top/left)	18h00m14s.57
RA (top/right)	17h55m36s.60
RA (bottom/right)	17h56m52s.30
RA (bottom/left)	18h01m33s.73

Dec (center)	+66°38′12″.0
Dec (top/left)	+66°22′47″.2
Dec (top/right)	+66°33′18″.7
Dec (bottom/right)	+66°53′32″.2
Dec (bottom/left)	+66°42′52″.7

Image Index:

Contribution Index (beta):