NGC 4236

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2013/06/01 et 2013/06/15

Observation place


TelescopePlanewave 431mm – 17″, 2939mm FL, f/6,8
MountParamount ME
Imaging cameraSBIG STL-11000M - regulated at -20o Celsius
Image typeL (RGB)
ExhibitionLuminance (10 x 10 'bin 2 × 2), R, G and B (4 x 3' bin 3 × 3 each)
PretreatmentMaxim DL
TreatmentPhotoshop and PixInsight

Object description

Object typeBarred spiral galaxy
Visual magnitude9,6
Distance12 million light years
Diameter 91100 light years
Dimension seen from Earth23 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"