Abell 665 - Galaxy Cluster
Abell 665 is not necessarily one of the objects you usually find on any observing lists. This might be due to the fact that the light from this galaxy cluster
took 2.26 billion years to reach us and objects at this distance need a very large aperture and a very dark sky to be seen at all. But because the universe is
expanding, Abell 665 is no longer 2.26 billion light years away from us, but even 2.45 billion light years. So it has moved almost 200 million light-years
away from us - at a current speed of 50,000 km/s.
The special thing about Abell 665 is that it is the only galaxy cluster in the Abell Catalog (AGC) that belongs to Richness Class 5. What does this mean?
It means, that more than 300 galaxies in this huge cluster are at most 2mag fainter than the third brightest galaxy. 300 galaxies doesn't sound like much, but
once you look at an image of the HST of Abell 665, you understand the significance. It is a stunningly beautiful image. In the middle of this cluster there is
a huge elliptical galaxy, but only a few arcseconds in size because of the distance. It has the easy to remember designation "2MASX J08305736+6550299".
And exactly this galaxy was the target of my observation, but 2.3 billion lightyears deep in the infinite blackness of the universe there is not much to see
with 20" aperture - even if the object is a giant ellipse.
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So I was really curious when I could finally point my 20" f/3.2 at the position of Abell 665. Was there anything to see at all? And if so, what could be seen? The sky
above me was dark and the wind whispered softly in the firs. The stars twinkled only slightly, a sign of good seeing. High above my head the "Big Dipper" was visible,
home of Abell 665.
Along star patterns I went towards Abell 665 and after a few minutes I saw the star chain I was looking for, which should guide me to the giant ellipse. I turned
up the magnification to almost 400x and the sky background became pitch black. I easily recognized the stars visible on the Hubble image. But there was no trace
of the galaxy. Only darkness and the lonely twinkling of the faint stars....
After a few minutes, a diffuse something flashed out several times for a very brief moment: the galaxy I was looking for in the heart of Abell 665 - 2.5 billion
light-years away from us.
It was an incredible moment to see a galaxy at this distance with my own eyes. A galaxy that is moving away from us faster all the time and will disappear
from our field of view for all eternity in the far future - without a chance for us to ever see this galaxy again afterwards...
