NGC4631, Whale Galaxy

2019-04-25 / Click on image to enlarge

"Result of a gravitational interaction."

NGC 4631 is a big beautiful spiral galaxy. Seen edge-on, it lies only 25 million light-years away in the northern constellation Canes Venatici. The galaxy's slightly distorted wedge shape suggests to some a cosmic herring and to others its popular nickname, The Whale Galaxy. Either way, it is similar in size to our own Milky Way.

A companion galaxy, the small elliptical NGC 4627, is just above the Whale Galaxy. Off the lower edge of the picture lies another distorted galaxy, NGC 4656, also called The Hockey Stick Galaxy. The galaxy has been significantly distorted through interaction with its large neighbor NGC 4631. A particulary bright knot in the blade of the hockey stick has been assigned the seperate NGC number NGC 4657. Beyond this knot, the galaxy curves up giving it the characteristic shape.

Technical Details

LocationZollikerberg, Switzerland
CameraNikon DSLR D810A
TelescopeTS ONTC 12" f/4 Carbon Newton
Special LenseTS 2,5" Wynne Coma Corrector
MountiOptron CEM60 Center-Balanced Equatorial Mount
AutoguidingLacerta MGEN2 (Autoguiding, Dithering)
Planetarium SoftwareStellarium
Image Session ControlAPT - Astro Photography Tool v3.5, ASCOM Platform 6
Lights63 x 120s (total 2h06'), ISO-1600, additional Biases, Flats, no Darks
Stacking SoftwarePixinsight 1.8, Drizzle 2x
Image ProcessingPixinsight 1.8