Galaxy group Holm(-berg) 124

[wimvb]

Holm 124 or Holmberg 124 or LGG 173 is a group of four interacting galaxies in the constellation Ursa Major. Both "Holm" and "Holmberg" are used as names for this group. The latter makes more sense to me, since there are several Holmberg objects, but I hadn't heard the name "Holm" before.

Anyway, the largest galaxy in the group, ngc 2805 is at a distance of approximately 80 million light years, while the other members are somewhat closer; 72 - 75 Mly.

Ngc 2805 was discovered by William Herschel in 1791. This is a barred spiral galaxy with a diameter of about 149 000 light years, almost 50% larger than the Milky Way. In this fov, it only covers 6.3 x 4.8 arcminutes.

The edge on galaxy in this image is ngc 2820, approximately 74 million light years distant and 85 000 light years across. The tiny galaxy at its lower tip is IC 2458 or ngc 2820A, a lenticular dwarf galaxy, only 10 000 ly across.

Finally in this group is ngc 2814, just to the right of ngc 2820. This barred spiral galaxy, also seen edge on, is approximately 25 000 ly across.

Quite a bit further away are galaxy clusters [AM2011] 2 (near the lower right corner of the image, looking like a swarm of gnats) and SDSSCGB 30048 (just above the larger red star in the lower right corner). The former has about 50 members and is at a distance of 1.6 billion light years, while the latter is at a distance of 1.8 billion light years.

Capture details:

Telescope: MN190 on a AZ-EQ6

Camera: ASI294MM with Optolong LRGB filters

Exposures: L 145 x 150 s; R 42 x 150 s, G 40 x 150 s, B 52 x 150 s Total integration time: 11.5 hours. Captured last February.

Edited April 26, 2021 by wimvb
Holm or Holmberg?

[peter shah]

beautiful process with lovely star colour

[wimvb]

Thanks, Peter. This wasn’t an easy image. The galaxy is very faint, and needs a lot of data to lift it from the noise floor. I also have Ha, but so far I haven’t managed to incorporate it the way I would like it.

[callisto]

Great Image and very informative...thanks 👍

 

Mark