2025 Sept. 16 ~ Barnard's Galaxy (NGC 6822) in the constellation Sagittarius
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Photographed at Algonquin Provincial Park, Ontario, Canada
(285 km by road north of Toronto)
between 23.30 and 23.50 EDT
* Total exposure time: 10 minutes
* 660 mm focal length telescope
* Field of view: ~2.8° wide x 1.7° high
* Altitude of galaxy at time of exposures: 22.5°, declining to 20.4°
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Description:
This was my first attempt at photographing this magnitude 8.8 galaxy, which is famous in the history of astronomy, as you will see from reading the description below:
From Wikipedia:
"NGC 6822 (also known as Barnard's Galaxy, IC 4895, or Caldwell 57) is a barred irregular galaxy approximately 1.6 million light-years away in the constellation Sagittarius. Part of the Local Group of galaxies, it was discovered by E. E. Barnard in 1884, with a six-inch refractor telescope. It is the closest non-satellite galaxy to the Milky Way, but lies just outside its virial radius. It is similar in structure and composition to the Small Magellanic Cloud. It is about 7,000 light-years in diameter.
Edwin Hubble, in the paper N.G.C. 6822, A Remote Stellar System, identified 15 variable stars (11 of which were Cepheids) of this galaxy. ... Hubble's detection of eleven Cepheid variable stars was a milestone in astronomy. Utilizing the Cepheid Period-Luminosity relationship, Hubble determined a distance of 214 kiloparsecs or 698,000 light-years. This was the first system beyond the Magellanic Clouds to have its distance determined. (Hubble continued this process with the Andromeda Galaxy and the Triangulum Galaxy). This distance to the galaxy was way beyond Harlow Shapley's value of 300,000 light-years for the size of the universe. In the paper, Hubble concluded the "Great Debate" of 1920 between Heber Curtis and Shapley over the scale of the universe and the nature of the "spiral nebula". It soon became evident that all spiral nebulae were in fact spiral galaxies far outside our own Milky Way."
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Technical information:
Nikon D810a camera body on Tele Vue 127is (127 mm - 5" - diameter) apochromatic refracting telescope, mounted on a Sky-Watcher EQ6-R PRO SynScan mount
Ten stacked subframes - each frame:
660 mm focal length
ISO 3200; 1 minute exposure at f/5.2, unguided, with long exposure noise reduction
Stacked in RegiStar 1.0.10
Processed in Photoshop CS6 (brightness, contrast, colour balance)
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2025 Sept. 16 ~ Barnard's Galaxy (NGC 6822) in the constellation Sagittarius
****************************************************************************
Photographed at Algonquin Provincial Park, Ontario, Canada
(285 km by road north of Toronto)
between 23.30 and 23.50 EDT
* Total exposure time: 10 minutes
* 660 mm focal length telescope
* Field of view: ~2.8° wide x 1.7° high
* Altitude of galaxy at time of exposures: 22.5°, declining to 20.4°
___________________________________________
Description:
This was my first attempt at photographing this magnitude 8.8 galaxy, which is famous in the history of astronomy, as you will see from reading the description below:
From Wikipedia:
"NGC 6822 (also known as Barnard's Galaxy, IC 4895, or Caldwell 57) is a barred irregular galaxy approximately 1.6 million light-years away in the constellation Sagittarius. Part of the Local Group of galaxies, it was discovered by E. E. Barnard in 1884, with a six-inch refractor telescope. It is the closest non-satellite galaxy to the Milky Way, but lies just outside its virial radius. It is similar in structure and composition to the Small Magellanic Cloud. It is about 7,000 light-years in diameter.
Edwin Hubble, in the paper N.G.C. 6822, A Remote Stellar System, identified 15 variable stars (11 of which were Cepheids) of this galaxy. ... Hubble's detection of eleven Cepheid variable stars was a milestone in astronomy. Utilizing the Cepheid Period-Luminosity relationship, Hubble determined a distance of 214 kiloparsecs or 698,000 light-years. This was the first system beyond the Magellanic Clouds to have its distance determined. (Hubble continued this process with the Andromeda Galaxy and the Triangulum Galaxy). This distance to the galaxy was way beyond Harlow Shapley's value of 300,000 light-years for the size of the universe. In the paper, Hubble concluded the "Great Debate" of 1920 between Heber Curtis and Shapley over the scale of the universe and the nature of the "spiral nebula". It soon became evident that all spiral nebulae were in fact spiral galaxies far outside our own Milky Way."
__________________________________________
Technical information:
Nikon D810a camera body on Tele Vue 127is (127 mm - 5" - diameter) apochromatic refracting telescope, mounted on a Sky-Watcher EQ6-R PRO SynScan mount
Ten stacked subframes - each frame:
660 mm focal length
ISO 3200; 1 minute exposure at f/5.2, unguided, with long exposure noise reduction
Stacked in RegiStar 1.0.10
Processed in Photoshop CS6 (brightness, contrast, colour balance)
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