Galaxy Cluster Abell 2029 and IC 1101
There are elliptical galaxies, there are giant elliptical galaxies, and there is IC 1101, the mother of all giant elliptical galaxies, so to speak. It is probably the
largest known galaxy in the universe at this point in time.
But back to the beginning. IC 1101 is a galaxy of the type "cD". The small "c" stands for "central" and the big "D" for "diffuse". So "cD" means, that IC 1101
is found in the center of the galaxy cluster Abell 2029 and has a huge diffuse halo. How huge? Quite huge! Because the halo has no fixed boundary, there are
of course different opinions about where the galaxy actually ends. But with a diameter of 4 million light years one is certainly not so wrong. According to
another definition, one can also take the radius inside which 50% of the light is emitted. This radius is 210,000 light years for IC 1101. For comparison: Messier
87, one of the largest galaxies of the Virgo Cluster, has a radius of 25,000 light years. According to this definition IC 1101 is 8 times larger in diameter and has
600 times the volume of Messier 87. For the number of stars in IC 1101 one finds the absolutely unimaginable number of 100 trillion!
But where do these huge galaxies come from? It is assumed that they originate from the merger of giant elliptical galaxies. Some of them have multiple
nuclei, each emitting powerful X-ray emissions. This suggests the presence of multiple supermassive black holes. IC 1101 could also hide such a monster.
The almost incredible dimensions of IC 1101 are also reflected in the mass of the SMBH - one assumes 40...100 billion solar masses this black hole
could bring on the scale. Simply unbelievable!
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But enough of the preface - let's get to the eyepiece! With 20" aperture IC 1101 is not very difficult - despite the distance of more than one billion light years.
Seeing this glimmer of light for the very first time is a wonderful experience, especially when you know what's going on there. It's hard to put into words
when you're standing on top of the mountain, the stars twinkling above you, the wind rustling in the fir tops, and you see this small, diffusely glowing patch
of light - in reality, the largest known galaxy in the universe with a 100 trillion stars! Do you really need 50cm aperture? Probably not. IC 1101 should be visible
even with 16".
But the many other galaxies in the near vicinity are not so easy to see. I spent quite a while at 270x under my black cloth, looking for one galaxy after the other,
seeing them appear out of the darkness and then crossing them off my chart. This took a bit of time - because if I'm honest, my eyes kept wandering back to IC 1101....
