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Cat’s Eye Nebula is probably one of the most difficult targets that I ever shot.
It’s a really tough nut to crack with the core being extremely bright. Because of how bright it is and the fact that I’m using a Newtonian, it made 4 thick diffraction spikes around it. Luckily, I had some old data shot with a refractor, without the diffraction spikes, so I blended in the refractor data to the centre of the nebula, to eliminate the spikes. For the very centre, the little one, I had to shoot some short exposures with the ASI294M in bin 1×1 mode, and blended them in to show some details in there too, rather than having an overexposed blob.
To get to this result, I kept shooting, stacking, shooting and stacking again, until I felt that I have enough data.
I’m really happy with the final result and I hope you like it too.
Cat’s Eye Nebula
NGC 6543, also known as the Cat’s Eye Nebula, is a planetary nebula located approximately 3,000 light-years away in the constellation Draco. It’s one of the most complex and visually stunning planetary nebulae, exhibiting intricate structures like concentric shells, shock-induced knots, and high-speed jets. The nebula is a result of a dying star’s outer layers being ejected into space.
Discovered by William Herschel on February 15, 1786, it was the first planetary nebula whose spectrum was investigated by the English amateur astronomer William Huggins, demonstrating that planetary nebulae were gaseous and not stellar in nature.
At the centre of the Cat’s Eye Nebula is a dying Wolf–Rayet star shining at magnitude +11.4.
Equipment used:
Mounts: StellarDrive GT6, Dark Frame hypertuned EQ6
Modified Sky-Watcher Explorer 200p (Baader Diamond Steeltrack focuser), Orion Optics CT8, TS65Q quadruplet Apo refractor
Aplanatic coma corrector, Skywatcher 0.9x coma corrector
ASI294MM Pro Cmos camera, cooled at – 15°C
QHY268M Pro Cmos camera, cooled at – 10°C
Qhyccd QHY183M Coldmos, cooled at – 20°C
7×1.25″ Starlight Xpress USB filterwheel
8×1.25″ ZWO USB filterwheel
QHYCCD QHYCCD CFW3M-US 36mm filterwheel
Baader H-alpha 7nm 1.25″, Baader O-III 8.5nm 1.25″
Chroma 1.25″ RGB and 3nm Ha, Oiii filters
Antlia 36mm 3nm Ha, Oiii and RGB filters
QHYCCD QHY5L-II M
ZWO ASI290m Mini guide
ZWO OAG
QHYCCD OAG-M
Qhyccd Polemaster
Software used:
Eqmod, SGP – Sequence Generator Pro, PHD2, Stellarium, SharpCap for polar alignment
Date 12.05 to 01.06.2020 and 29.03.2025 to 17.04.2025
Location:
Bushey, Hertfordshire, Bortle 7 and Hemel Hempstead, Hertfordshire, bortle 5
Frames:
Antlia 3nm Narrowband H-alpha 36 mm: 50×120″(1h 40′)
Antlia 3nm Narrowband H-alpha 36 mm: 77×600″(12h 50′)
Antlia 3nm Narrowband Oxygen III 36 mm: 56×600″(9h 20′)
Antlia V-Pro Blue 36 mm: 12×120″(24′)
Antlia V-Pro Blue 36 mm: 5×600″(50′)
Antlia V-Pro Green 36 mm: 12×120″(24′)
Antlia V-Pro Green 36 mm: 5×600″(50′)
Antlia V-Pro Red 36 mm: 12×120″(24′)
Antlia V-Pro Red 36 mm: 5×600″(50′)
Baader H-alpha 7nm 1.25″: 57×300″(4h 45′)
Baader O-III 8.5nm 1.25″: 56×300″(4h 40′)
Chroma Blue 1.25″: 10×300″(50′)
Chroma Blue 1.25″: 24×60″(24′)
Chroma Blue 1.25″: 30×10″(5′) bin 1×1
Chroma Green 1.25″: 10×300″(50′)
Chroma Green 1.25″: 25×60″(25′)
Chroma Green 1.25″: 30×10″(5′) bin 1×1
Chroma H-alpha 3nm Bandpass 1.25″: 20×120″(40′)
Chroma H-alpha 3nm Bandpass 1.25″: 57×300″(4h 45′)
Chroma H-alpha 3nm Bandpass 1.25″: 73×600″(12h 10′)
Chroma H-alpha 3nm Bandpass 1.25″: 50×60″(50′) bin 1×1
Chroma OIII 3nm Bandpass 1.25″: 100×60″(1h 40′)
Chroma OIII 3nm Bandpass 1.25″: 23×600″(3h 50′)
Chroma OIII 3nm Bandpass 1.25″: 94×30″(47′) bin 1×1
Chroma Red 1.25″: 10×300″(50′)
Chroma Red 1.25″: 24×60″(24′)
Chroma Red 1.25″: 30×10″(5′) bin 1×1
Total integration time: 65h 37′
Stacked and calibrated in AstroPixel Processor and processed in Pixinsight (with help from Blur Xterminator, Star Xterminator and Noise Xterminator) and Photoshop CC 2025