Abell 1758 - Galaxy Cluster
Abell 1758 is located at a distance of 3.2 billion light-years in the constellation of the Hunting Dogs (CVn) and contains several 100 galaxies.
This is not a single cluster, but a collision of 4! galaxy clusters, which will merge into an extremely large structure in the form of a supercluster in the
near future. The two main components are designated "A1758N" and "A1758S", where N and S stand for "north" and "south". They are currently 2.4
million light-years apart. The northern component can even be divided into an eastern and a western part.
The whole construct is surrounded by a huge radio halo, which suggests that the merging process is not yet complete. Two diffuse radio sources
have also been found, although it is not yet entirely clear what they might be.
The brightest galaxy bears the inconspicuous name "2MASX J13443777+3810077" and is one of the largest known galaxies with a longitudinal
extent of no less than 730,000 light-years!
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Due to the huge distance of more than 3 billion light-years, not much can be seen even with a comparatively large aperture of 20".
Under a very dark sky, I could only see 3 extremely faint condensations at a magnification of 380x. Among them was the brightest galaxy "A1758
N BCG" (blue arrow), although I am not sure whether this was the galaxy itself or rather the combined light of several closely packed galaxies.
Observation is also difficult because there are hardly any brighter field stars to determine the exact position of the condensations. So you just look
into the darkness and hope, that you are looking at the right spot with averted vision to catch some of the few photons, that have been traveling for
many billions of years. :)
