NGC4631 Whale galaxy is located in Canes Venatici constellation (Hunting Dogs). Despite its uncommon shape it is actually a barred spiral galaxy seen edge-on from Earth. NGC4631 contains central starburst, that is a region of intense star formation – this is evident in the emission from ionized hydrogen and interstellar dust. Whale galaxy is similar size to our own Milky Way and is placed about 25 million light years away. Together with NGC4627 dwarf elliptical galaxy it forms a “double” galaxy, or galaxy pair, as it is described in the Atlas of Peculiar Galaxies. This pair is often referred to as the “Whale and Pup”.

Whale galaxy is also an excellent visual target. It is pretty bright and also its apparent dimensions are quite large (15 arc minutes). Can be spotted with binoculars, and under dark sky with large telescope the view is impressive, and its complex shape with much texture and mottling is clearly visible.

Image below is luminance only shot at my backyard observatory. It is stack of 60 frames, 3 minutes each. Made with Meade ACF10″ telescope and QHY163M camera on EQ6 mount. Both transparency and seeing were good this night.

NGC4631 Whale galaxy
NGC4631 Whale galaxy

Large version


And also filled with colours, that were collected with the same setup. These were made with Baader RGB filters, 37 frames, 3 minutes each.

NGC4631 Whale galaxy - LRGB stack
NGC4631 Whale galaxy – LRGB stack

Large version

Clear skies!

Image technical data: 

Date: 17,19.04.2018 
Location: Nieborowice, Poland 
Telescope: Meade ACF 10" 
Corrector: AP CCDT67 
Camera: QHY163M, gain 0 
Mount: SW EQ6 
Guiding: SW 80/400 + ASI290MM 
Exposure: L 60x3, RGB 15:10:12x3 minutes 
Conditions: seeing good, transparency average