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The Coma Cluster of Galaxies.  A Wide(ish) View, Alan Brunelle
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The Coma Cluster of Galaxies. A Wide(ish) View

Getting plate-solving status, please wait...
The Coma Cluster of Galaxies.  A Wide(ish) View, Alan Brunelle
Powered byPixInsight

The Coma Cluster of Galaxies. A Wide(ish) View

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Acquisition details

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Description

Maybe this is inappropriate, but I am updating this with a new revision that includes new data. I had collected some 360 sec subs (vs the 240s of the original) on a subsequent imaging night that was particularly nice. Otherwise no change to camera gain or offset settings. I wanted to see if I could go deeper. Does not seem so. Turns out that the added time also adds the added threat of guiding issues along with a breeze, so of the many subs I collected I brutally pared those down to the remaining few good subs. This also allowed me to be brutal in assessing the 240 sec subs from the original and with the best, I recalibrated both sets with appropriated darks, flats and biases and integrated those. This is the result. In the end, maybe a bit sharper. The small edge-on galaxies are a bit less "fat" and most galaxies have nuclei that are more stellar than on the initial image. Because my alignments between the two nights were not perfect, my field is cropped a bit from the original version.

Acquisition details do not allow me to state the different dates and sub conditions, so: 18 x 360 sec plus 22 X 240 sec for 3.27 hrs of total integration time. Readout mode 3, gain 0 and offset 8. Mostly I pared subs based on star shape and size to try to improve detail and contrast.

As previous:

A relatively wide view of the Coma galaxy cluster, dominated by two supergiant elliptical galaxies NGC 4874 and NGC 4889 at the center of the image. They are are also pretty much at the center of the cluster and are stated as being over 320 million light years distant (At least as of 320 million years ago!). Wikipedia states that this cluster is dominated by elliptical galaxies, ranging from the supergiant through dwarf. This makes for a less than dramatic portrait. Neither much in the way of structure nor color. Ellipticals are thought to be evolved, stable and largely composed of older stars. The tan color of the two giants attest to that. Large-scale star formation likely halted billions of years ago in these old galaxies and their dust, either ejected by their super massive black holes, or evenly distributed by some as yet discovered mechanism. For me, the most interesting objects are the two face on spirals at 12 and 1 o'clock from center. And while the many ellipticals do not necessarily stand out, it makes for easy detection of the scattering of spiral galaxies that are presented at just about every viewing angle to us. Just wish were were a lot closer!

I chose this target because of its rather compact nature as seen on my chart. It also appeared to easily fit into my field of view. My subs were 240 seconds, but at 0 gain on the deepest well setting for my camera. It was my hope that I would be able to get this to go deep. As it turns out, there have to be at least several hundred galaxies identified via PI Render (says 584 here) and it turns out, at least several times that, which are clearly galaxies, yet are not listed. In fact, while processing at a detailed level, it is clear that the whole field is dense with fuzzies that are no doubt galaxies either far beyond this cluster, or are the many dwarf galaxies that are known to exist. Some of these are congregated into groups that are no doubt galaxy cluster that themselves may rival this great cluster. I am not sure that my processing has preserved all these fuzzies nor during the workup to jpg for upload here. Given the signal and background I got with the 240 sec subs, I am sure I could increase that time significantly and try to tease out more, but the few bright foreground stars would likely become problematic.

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  • The Coma Cluster of Galaxies.  A Wide(ish) View, Alan Brunelle
    Original
  • Final
    The Coma Cluster of Galaxies.  A Wide(ish) View, Alan Brunelle
    C

C

Description: I started to load this into a completely new image but thought that to be wasteful. This image includes a subset of data from my first posting but with new data as well. I will revise the information in this post to cover the new data and processing.

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The Coma Cluster of Galaxies.  A Wide(ish) View, Alan Brunelle