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| NGC 6543 - the Cat's Eye Planetary Nebula EdgeHD11/ASI2600mm - 42x600sec Ha; 43x600sec O3 14 hours integration time May 31, June 2 and June 5, 2023 |
This is the famous Cat's Eye nebula, a remarkable planetary nebula (PN) located in the constellation of Draco the dragon. It was discovered by William Herschel on February 15, 1786. It resides at an estimated distance of 3,262 light years from earth. The inner core is about 16 arc sec in diameter, which at it's current distance would make it about 0.25LY wide. Images from the Hubble telescope made this object a subject of popular review when they showed the central core of the nebula in exquisite detail, revealing knots, jets, bubbles and complex arcs, all being illuminated by the central hot planetary nebula nucleus. My image shows the surrounding outer halo (about 4.7LY in diameter) in the HOO NB color palette. Both the central WR:+O7 spectral class PNN star and the concentric rings surrounding the inner core can be plainly seen. Based on both the estimated distance and the expansion rate the age of this PN is about 800-1200 years old.
The image was composed of 42 Ha subs and 43 O3 subs, each 600 seconds of exposure. Since the nucleus of the nebula is so very bright (shining at magnitude 8) the 600 seconds really washed out the core and so I had to carefully process the image with a High Definition layer routine to bring out some of the internal detail and reduce the overall intensity. There is evidence of some processing artifacts present, but adding more data later will probably resolve that issue. I had also planned to capture RGB stars to replace the NB stars, but between the full moon and the smoke drifting into Maryland from the Canadian fires I had to forgo those and settle on the NB stars. I hope to replace them with RGB stars when I capture more data of this wonderful object.
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