NGC253 - Sculptor Galaxy

Name: Sculptor Galaxy, NGC 235
Type: Spiral galaxy
Distance: ~11.4 million of light-years
Diameter: ~70.000 light-years [2]
Apparent magnitude: 8
Constellation: Sculptor [1]

The Sculptor Galaxy, also known as the Silver Coin or Silver Dollar Galaxy, NGC 253, is an intermediate spiral galaxy in the constellation Sculptor. The Sculptor Galaxy is a starburst galaxy, which means that it is currently undergoing a period of intense star formation.[1]

The galaxy was discovered by Caroline Herschel in 1783 during one of her systematic comet searches. About half a century later, John Herschel observed it using his 18-inch metallic mirror reflector at the Cape of Good Hope. He wrote, "very bright and large (24' in length); a superb object.... Its light is somewhat streaky, but I see no stars in it except 4 large and one very small one, and these seem not to belong to it, there being many near..."[1]

As one of the brightest galaxies in the sky, the Sculptor Galaxy can be seen through binoculars and is near the star Beta Ceti. It is considered one of the most easily viewed galaxies in the sky after the Andromeda Galaxy.[1]

The Sculptor Galaxy is a good target for observation with a telescope with a 300 mm diameter or larger. In such telescopes, it appears as a galaxy with a long, oval bulge and a mottled disc. Although the bulge appears only slightly brighter than the rest of the galaxy, it is fairly extended compared to the disk. In 400 mm scopes and larger, a dark dust lane northwest of the nucleus is visible, and over a dozen faint stars can be seen superimposed on the bulge.[1]

Source:
[1] Wikipedia - en.wikipedia.org/wiki/Sculptor_Galaxy
[2] ESO - European Southern Observatory - www.eso.org/public/images/eso0902c/

I registered this picture in two sessions: July, 18th 2015 in Padre Bernardo - Goiás - Brazil during the 8th Brazilian Meeting of Astrophotography and other session at August, 16th 2015 in rural zone of São Pedro - São Paulo - Brazil.

Technical data:
ISO 800, 4h30m of exposition (54 subs), darks (200), flats (~250) e bias (200).

Equipment:
- Equatorial Mount Orion Atlas EQ-G
- GSO Ritchey-Chretien Telescope 8" F8
- Canon DSLR 500D modded with Astrodon filter
- Focal reducer Astro-Physics 67 CCDT
- Guided with ASI120MM ZWO using OAG
- Astronomik CLS clip filter (in 2nd session)

Software
- Capture: BackyardEOS
- Processing: PixInsight 1.8, eXcalibrator and Adobe Photoshop CS5
- Guiding: PHD2