Hockey Stick and Whale galaxies

Image Detail:

Here is the beautiful pair of the Hockey Stick (NGC 4656) and Whale galaxies (NGC 4631) in the constellation Canes Venatici. There are dozens of other more distant galaxies in the background that were too faint to plate solve.

The smaller “Hockey Stick Galaxy” on the left is mainly blue because of the large amount of young blue stars. Typically, abundance of star birth activity indicates some violent event, which triggered the condensation of gas clouds into proto-stars, which lead to occurrence of many new young stars. Such event is very often merger of two galaxies and the slightly irregular shape of NGC4656 and also streams of stars reaching far from the galaxy spiral arms hint such merger occurred only recently.

The larger Whale Galaxy at right is probably rather typical spiral galaxy, but visible from the side. It shows a yellow and orange central bulge, composed mainly of old stars, as well as dark interstellar dust lanes and dark reddish hydrogen clouds around the galaxy disk. Light blue portions indicate presence of many bright, young blue stars consuming the outer arms.

OTA: Explore Scientific ED152 Air-Spaced Triplet 1216mm focal length⁣ f/8
Mount: Celestron CGX-L
Camera: ZWO ASI2600MM Pro
Gain: 100
Cooling Temperature: -10 Celsius
Auto-guiding: ZWO ASI174MM Mini and ZWO M68 OAG
Control: ZWO ASIAIR Pro
Filters: 2" Astronomik L3, RGB (CCD), Ha (12nm)

Acquisition:
L 60 x 300s = 5 hours
R 31 x 600s = 5.2 hours
G 31 x 600s = 5.2 hours
B 31 x 600s = 5.2 hours
Ha 15 x 900s = 3.75 hours
24.35 hours total

Flagstaff, AZ - Bortle 4 skies
Calibrated in Astro Pixel Processor⁣ with darks and flats
Processed in Pixinsight and Lightroom

Copyright: Drew Evans