Hemisphere:  Northern  ·  Constellation: Draco (Dra)  ·  Contains:  Cat's Eye Nebula  ·  NGC 6543
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NGC 6543, 



    
        

            Robert St John
NGC 6543
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Getting plate-solving status, please wait...
NGC 6543, 



    
        

            Robert St John
NGC 6543
Powered byPixInsight

Equipment

Imaging Telescopes Or Lenses
Celestron C9.25
Imaging Cameras
QHY 183 Cooled Color QHY 183
Mounts
Orion Sirius Pro Go-To
Filters
Optolong OIII
Accessories
f/6.3 Focal Reducer & Corrector
Software
Fitswork4 · SharpCap Pro · DeepSkyStacker (DSS) deepskystacker · Jasc Paint Shop Pro 8
Guiding Telescopes Or Lenses
ZWO 60/280 Guiderscope

Acquisition details

Dates:
July 7, 2020
Frames:
15x433" (1h 48' 15")
Integration:
1h 48' 15"
Avg. Moon age:
17.10 days
Avg. Moon phase:
93.97%

Basic astrometry details

Astrometry.net job: 4398664

RA center: 17h58m31s.7

DEC center: +66°3813

Pixel scale: 0.692 arcsec/pixel

Orientation: 38.326 degrees

Field radius: 0.153 degrees

Resolution: 1184x1059

Locations: Home observatory, Barstow, United States

Data source: Backyard

Description

1897 memoir, which reflect Herschel's ideas and reveal his thrill at his great discovery:

"On the evening of August 29, 1864, I directed the telescope...to a planetary nebula in Draco. The reader may be able to picture to himself...the feeling of excited suspense, mingled with a degree of awe, with which, after a few moments of hesitation, I put my eye to the spectroscope. Was I not about to look into a secret place of creation?

I looked into the spectroscope. No such spectrum as I expected! A single bright line only! ... The light of the nebula was monochromatic, and so, unlike any other light I had yet subjected to prismatic examination, could not be extended out to form a complete spectrum...A little closer looking showed two other bright lines on the side towards the blue. The riddle of the nebulae was solved. The answer, which had come to us in the light itself, read: Not an aggregation of stars, but a luminous gas" [emissions being characteristic of hot gases under low pressure].

Huggins had discovered an emission line of hydrogen in the blue part of the spectrum and two "mystery lines" in the green that were later thought to come from an unknown element called "nebulium." Among the strongest emissions in planetary nebulae, the "nebulium" lines were finally found by I. S. Bowen in 1928 to be emissions of doubly-ionized oxygen.

Comments

Revisions

  • NGC 6543, 



    
        

            Robert St John
    Original
  • NGC 6543, 



    
        

            Robert St John
    B
  • NGC 6543, 



    
        

            Robert St John
    C
  • Final
    NGC 6543, 



    
        

            Robert St John
    D

Sky plot

Sky plot

Histogram

NGC 6543, 



    
        

            Robert St John

In these public groups

ZWO ASI183/QHY183