NGC 4631

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Observation place
New Mexico


TelescopeTakahashi Epsilon 250 - 10 ″, 850mm FL @ f / 3.4
MountParamount ME
Imaging cameraSBIG ST10XME - Non Anti Bloomin Gate (NABG) regulated at -15o Celsius
Image typeL (RGB)
ExhibitionLuminance (12 x 5 'bin 1 × 1), R and B (4 x 2,5' bin 2 × 2 each) and V (3 x 2,5 'bin 2 × 2)
PretreatmentMaxim DL
TreatmentPhotoshop and PixInsight

Object description

Object typeSpiral galaxy "The whale galaxy"
ConstellationHunting dogs
Visual magnitude9
Distance25 million light years
Diameter 140000 light years
Dimension seen from Earth15,2 x 2,8 arc minutes 
NGC 4631, also called the Whale Galaxy, is a spiral galaxy seen from the side. It is at a distance of about 25 million light years from Earth in the constellation Hunting Dogs. It is in gravitational interaction with galaxy NGC4627, which can be seen in the image just above galaxy NGC4631. This gravitational movement gives it an irregular shape, thus offering a resemblance to that of a whale, from which it takes its name.  

It is a very beautiful galaxy to photograph. Its visual magnitude of 9 makes it accessible in medium-diameter telescopes.
Richard Beauregard
Sky Astro - CCD
My impression "We cannot be alone in this gigantic universe"