Corona Borealis Galaxy CLuster
Posted 18 September 2013 - 10:11 PM
The co-ordinates are: 15h 20.5m, +27 deg. 50m.
A photo of this cluster appears in Burnham's Celestial Handbook, vol.2.
I would be interested in hearing from anyone else who has observed this amazing formation of galaxies.
Roy in Taos.
Posted 19 September 2013 - 12:20 AM
The brighter galaxies are in the ~16.5 magnitude range and are clustered around a couple of field stars just bright enough to be annoying but not so bright as to prevent seeing some of the brighter galaxies in this distant cluster.
I observed this group just a week and half ago under 21.35 SQM skies and had a pretty good view. It fell short of the view I had in August under 21.85 skies, but I expected that. What surprised me was that I could still see about half the galaxies I saw under the darker sky so I'm glad I gave it a shot.
I found using an eyepiece producing a 2mm exit pupil worked best, which in my case was an 8mm Ethos. Try a bunch of magnifications to see what works best for you though, you never really know until you try. For what it's worth, I had a tough time seeing even a couple of these galaxies with my old 20 inch years ago but looking back I didn't use enough magnification.
This is a great galaxy cluster and I hope you get a great view. It's sinking pretty low in the west now so you're best bet is to wait until spring, but with a great night you could get a good view during the next new moon cycle. Good luck!
Posted 19 September 2013 - 09:04 AM
- Roy in Taos
Posted 19 September 2013 - 04:02 PM
I was barely able to discern several members of AGC 2065 in my old 16-inch under mag 6 skies. With mag 7 skies and an 18-inch it was a bit easier to navigate the cluster. Howard has a lot more experience than I do at this, but I think in your case a 2mm exit pupil might yield insufficient power (although everyone has different responses to power and exit pupil...). Assuming your 18-inch is f/4.5, a 2 mm exit pupil corresponds to about 230X, while in Howard's 28-inch f/4, it's 355X. Of the two, I think power is the more important variable here: I would recommend using powers near 300X and above. Make sure you have a good photo to work from, such as Alvin Huey's or Steve Gottlieb's.
Posted 19 September 2013 - 11:57 PM
The best I've had with my scope using an image to guide me where to look was 18 direct galaxy sightings.
Posted 21 September 2013 - 02:20 PM
Posted 22 September 2013 - 03:00 AM
it was always tough for my 16" to pick up some galaxies within the cluster, a friend of mine uses the cluster with his 16" to test the sky quality. When I remember right he speaks about 5-6 galaxies in the center.
With my 27" under good conditions I could pick up 28 galaxies in the center 8'x8' field. It was a still tough an needs at least 3h of observing time to observe and sketch all for me possible galaxies.
Johannes Brachtendorf could pick up also around 20 galaxies with his 25". You have to scroll down a look in his map with the marked galaxies.
Posted 25 September 2013 - 07:00 AM
Roy in Taos
Posted 01 October 2013 - 09:34 PM