| Date 2013/06/01 et 2013/06/15 Observation place Spain |
Technical
| Telescope | Planewave 431mm – 17″, 2939mm FL, f/6,8 |
| Mount | Paramount ME |
| Imaging camera | SBIG STL-11000M - regulated at -20o Celsius |
| Image type | L (RGB) |
| Exhibition | Luminance (10 x 10 'bin 2 × 2), R, G and B (4 x 3' bin 3 × 3 each) |
| Pretreatment | Maxim DL |
| Treatment | Photoshop and PixInsight |
Object description
| Object type | Barred spiral galaxy |
| Constellation | Dragon |
| Visual magnitude | 9,6 |
| Distance | 12 million light years |
| Diameter | 91100 light years |
| Dimension seen from Earth | 23 x 8 arc minutes |
| NGC 4236 is a barred spiral galaxy located approximately 12 million light years from Earth. Despite its overall visual magnitude of 9,6, the arms of this galaxy have very low surface brightness. It is surely for this reason that there are not many amateur images of this galaxy. This is also what I noticed when photographing her. Using a 431mm (17 '') telescope helped achieve these low magnitudes (telescope visual magnitude of 16). Faith solved this difficulty, it is a very beautiful galaxy to photograph. It is presented in very beautiful shades of blue. To successfully resolve this image, I had to invest more time in processing. Indeed, even in this site without light pollution, the surface luminosity of the arms of the galaxy is very close to the background noise of the sky. By developing the arms (stretching), the background noise came out, which required more effort in the treatment. |
| Richard Beauregard Sky Astro - CCD My impression "We cannot be alone in this gigantic universe" |