NGC 4631, NGC 4627 and NGC 4656 are three gravitationally interacting galaxies that can be found about 25 million light-years away in the constellation Canes Venatici.

Shelley Jackson’s beautiful capture of the galaxies — photobombed by Comet Leonard — wins the Photo of the Week on December 3, 2021. 

NGC 4631 is known as the “Whale Galaxy” due to its shape being similar to that of a whale. The Whale Galaxy can be seen towards the centre of Jackson’s image, just slightly off to the right.

NGC 4627 is located slightly above the Whale, and is the small cluster of stars with a faint glow surrounding it. Known as the Pup Galaxy, it is a small elliptical galaxy that gets its name for being the smaller companion ‘pup’ to the Whale Galaxy.

Just underneath and slightly to the right of the Whale Galaxy is the comet  C/2021 A1 (Leonard), which Jackson captured in the early hours of November 24, 2021. 

Shooting from her Bortle 6/7 backyard in Sarnia, Ontario,Jackson switched mounts on her Sky-Watcher AZ EQ5 pro and adjusted the equipment just in time for the comet’s apparition at 3 a.m., giving her the perfect window to capture the icy traveller before clouds blocked the view 15 minutes later.

NGC 4656 is located towards the centre left of the image, and is known as the “Hockey Stick Galaxy.” NGC 4656 gets its nickname from its warped shape which shares a resemblance to a hockey stick. It is thought that this galaxy gets its unique shape due to an interaction between the Hockey Stick, Whale and Pup galaxies.

Galactic interactions have the potential to change the shape of celestial objects, which can include shifting and warping the gas of constituents, stars, and dust into the unique shapes such as the Hockey Stick Galaxy shows us.

Honourable mention

This week’s honourable mention goes to Dan Kusz, who brings us an image of IC 63 taken on September 11, 2021. Known as “the Ghost of Cassiopeia,” it is found 550 light-years away within the constellation Cassiopeia the Queen.

The image gets its red-hue due to hydrogen reacting with ultraviolet radiation. The reaction causes electrons within IC 63 to gain energy, which is then released as Hydrogen-alpha radiation in a visible red colour.

Kusz brings us this image from Vernon, British Columbia. The image was taken on a ZWO ASI2600MM Pro with a Sky-Watcher Esprit 120 lens with a focal length of 647mm. The exposure time for the image was 6.5 hours.