NGC 6822 (also known as Barnard’s Galaxy, IC 4895, or Caldwell 57) is a barred irregular galaxy approximately 1.6 millionlight-years away in the constellation Sagittarius. Part of the Local Group of galaxies, it was discovered by E. E. Barnard in 1884 (hence its name), with a six-inch refractor telescope. It is one of the closer galaxies to the Milky Way. It is similar in structure and composition to the Small Magellanic Cloud. It is about 7,000 light-years in diameter.
Edwin Hubble wrote the seminal paper N.G.C. 6822, A Remote Stellar System (Hubble 1925) wherein he identified 15 variable stars (11 of which were Cepheids). He also surveyed the galaxy’s stars distribution down to magnitude 19.4. He provided spectral characteristics, luminosities and dimensions for the five brightest “diffuse nebulae” (giant H II regions) that included the Bubble Nebula and the Ring Nebula. He also computed the absolute magnitude of the entire galaxy.
Imaging telescopes or lenses: Geoptik “Formula25″ Newton 10” 1250mm
Imaging cameras: Home made 450D Cmos Cooled – Baader
Mounts: Sky-Watcher NEQ6
Guiding telescopes or lenses: 60/228
Guiding cameras: Shoestring Astronomy USB Guide Port Interface, Xbox LiveWebcam
Software: Pleiades Astrophoto, S.L. PixInsinght 1.8 RC7
Filters: Hutech IDAS LPS V4
Accessories: Baader MPCC mpcc coma correcteur
Dates: Aug. 6, 2013, Aug. 7, 2013, Aug. 8, 2013
Frames: Hutech IDAS LPS V4: 72×300″
Integration: 6.0 hours
Author: Giosi Amante
AstroPhotography of the day by SPONLI 31 July 2014