Messier 87 - Giant Elliptical Galaxy
In April 2019, the elliptical galaxy Messier 87 was the talk of the town: for the first time in the history of astronomy, an image of a supermassive
black hole was obtained and presented to the public. This was only possible due to the combination of many radio telescopes distributed all over
the globe. The appropriate name for it: Event Horizon Telescope, or "EHT" for short.
But first things first: Messier 87 is a giant elliptical galaxy with a diameter of 240,000 light-years, making it one of the largest and most massive
galaxies in our vicinity. It combines about 6 trillion solar masses and is surrounded by 12,000 globular clusters. With a distance of 54 million
light-years it belongs to the Virgo Cluster and is the second brightest galaxy in it - only surpassed by Messier 49. For a long time Messier 87 was
known as a radio and X-ray source and therefore also carries the names "Virgo-A" and "Virgo X-1".
In the center of this huge galaxy lurks a supermassive black hole (SMBH) with a mass of 6.5 billion solar masses and a diameter of almost 40
billion kilometers. Compared to this, even our solar system looks tiny. This SMBH produces a relativistic jet, which extends over a length of 20"
with a width of only 2" (arc seconds).
From these numbers, we can see that it is not easy to see this jet in the telescope. It is not in front of the black sky background, but directly in
the halo of Messier 87, so the contrast is not really high. So you need a dark sky, very good seeing, a large telescope, good optics and a high
magnification. If you have all this, the chances to see the jet are quite good.
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When I visited Messier 87 with my 20" f/3 Dobson, I first looked for the many surrounding galaxies, of which some were visible. One of the
brighter ones is unfortunately outside the drawing. Extremely difficult were the two tiny galaxies just outside the halo of Messier 87, so they
are only indicated in the drawing.
Now my eye was properly dark-adapted. The hunt for the jet could begin. With a magnification of 370x I noticed again and again an irregularity
at one spot of the halo, which could be held more and more clearly with indirect vision. After many minutes the shape peeled out slowly. The jet
looked like a very fine needle of light. Just beautiful!
In the next minutes I let the impression work on me again and again - you really can hardly tear yourself away from it. For me in any case one
of the most beautiful observations I have made so far.
