About image
NGC 6543, also called "Cat's Eye Nebula", is a planetary nebula visible in the constellation of the Dragon.
It has an apparent magnitude of 9.8 and a high surface brightness, although its apparent dimensions are rather small (20 "the core and about 6' the halo).
It is located at a distance of 3300 light years and is structurally one of the most complex nebulae currently known.
The image was obtained from my home terrace in conditions of strong light pollution due to sodium lamps of public lighting (value sqm: 18.67 at the zenith).
This result was achieved thanks to the use of narrow band interference filters and a long exposure divided over four nights.

Technical data
Optic          Celestron C9.25 Edge HD f/10
Mount        Losmandy G11 with Ovision worm and FS2
Camera         Atik 4000 with Starlight Xpress filter wheel 5 positions
Filters         Baader Ha 7nm and OIII 8.5nm, 50.8 unmounted
Guiding system    OAG LB Astro Proxima and Lodestar
Exposure details  Ha 24x20" + 22x900" bin1 -10C
                                     OIII 60x5" + 12x900" bin1 -15C + 9x900" bin1 -10C
Total integration   11h
Acquisition      Maxim, PHD2
Processing      Maxim, Photoshop CS5
SQM-L       18.67    
Location       Home terrace (Rescaldina, Italy)
Date           8/9 June, 5/15 July 2014