Galaxy Clusters - Off the beaten path

[Astrojedi]

After downloading Martin's deep maps I immediately set about putting them to good use. Here are some less visited (for very good reason as they are extremely faint) galaxy clusters. Also added a couple of the (relatively) brighter ones at the end for eye candy in case you get tired of looking for the really faint fuzzies. Hope you enjoy these.

I would say that many of these faint clusters are likely not visually observable in even large amateur telescopes even on a perfect night. But courtesy of EAA I was able to observe all of these on one one of the worst nights of the month.

I would rate the transparency as 2 or 3 out of 10. I imaged through a layer of light clouds due to which the sky was so bright that I could not even do 15s exposures. Hence resorted to 5s or 10s exposures and had to use summing instead of averaging to get any signal. The seeing was also at best average.

I was amazed I got anything at all. But honestly this has nothing to do with my skill rather everything to do with the equipment we have available to us.

Make sure you click on the image to open up the full resolution as some of the galaxies in the clusters are very faint. The approximate center of the cluster is marked.

Abell 372: A sparse, very distant but relatively bright cluster in Perseus with about 40 members

Abell 523: A rich but extremely distant cluster in Orion (distance class 6) with about 124 members. This one is on my list to try again on a better night.

Abell 526: Another distant cluster in Orion with 71 members

Abell 576: A not very rich (richness class 1 - scale goes from 0-6) but relatively bright cluster in Lynx with 61 members.

Abell 407: A relatively bright cluster in Perseus with about 46 members. Note that the lumpy looking galaxy system in the center with multiple cores is actually not a true member of the cluster

Abell 426 & 347: Both are member of the Perseus-Pisces Supercluster which is one of the largest known structures in the universe at about 250M ly away

[RobertI]

Great captures, I love zooming in on the clusters, like using a super-zoom eyepiece, very immersive.

[Astrojedi]

Thanks Rob. I do like the FOV of the Ultrastar and the finer pixel pitch. Gives a sense of depth.

[laudropb]

Very nice captures. Always nice to see something a bit different every now and again. Thanks for posting.

[Martin Meredith]

These are great under the conditions, and using 10s subs must have made the whole observing experience quite compelling.

Of course, I like them all, but I particularly like Abell 407. What is really impressive is the compact grouping in the centre of the cluster (known as VV 1060). Strangely, these galaxies seems to be absent from my maps, something I need to chase up…. is it really not part of the cluster?

Martin

[added in edit: It turns out that this is listed in HyperLEDA as a multiple galaxy, a category I've inexplicably ignored so far; OK, it will be on the next charts release sometime after xmas … keep posting the images: I find them useful for debugging!]

[Astrojedi]

Thanks Martin. I hate losing an opportunity to do some viewing hence pushed ahead despite the viewing conditions.

I have found that using sum for stacking allows me to go deeper quicker vs. mean when viewing the faint fuzzies and 10s is more than sufficient. The only drawback is that as sum does not normalize the histogram I am constantly tweaking the contrast/black level settings.