Ton 618 - Quasar
The quasar (QSO) "Ton 618" is located with a brightness of 15.9mag in the constellation "CVn" and can be observed best in spring.
It was first noticed in 1957 when a "violet" star was discovered on a photographic plate. Then in 1970 radio emissions were observed emanating from this
object and " Ton 618" was classified as a quasar. It has a redshift of z=2.2, which corresponds to a light travel time of 10.4 billion years. Due to the expansion
of the universe the distance has grown to 18.1 billion light years and every second the QSO moves away from us by another 246,000 kilometers. This
corresponds to 82% of the speed of light.
That we can see " Ton 618 " despite the huge distance is due to its immensely large absolute magnitude of M= -30.7mag, which corresponds to a luminosity
of 140 trillion suns. This makes it one of the most luminous objects in our universe and even at a distance of 200 light years the QSO would still shine as
bright as the sun in the daytime sky. The energy needed for this is generated by a huge ultramassive black hole (UMBH) with a mass of 40...66 billion solar
masses. That is more than the galaxy Messier 33 brings on the scale - it weighs "only" 50 billion solar masses. The UMBH is so huge that the radius of its
event horizon is 40x as large as the orbit of Neptune.
The quasar and the host galaxy are surrounded by a huge gas cloud with a diameter of 330,000 light years, which has a mass of 100 billion solar masses.
----------------------------------------------------------------------------------------------------------------------------------------------
On a particularly clear night I used my 20" f/3.2 to search for Ton 618. The quasar was found pretty fast because of its position in the sky.
The surrounding area is rich in "brighter" 13mag stars, so finding the QSO becomes an easy exercise. Then we have to look out for a faint 16mag "little star",
which then flashed again and again after a short time and could be held steadily at 270x.
By the way, there are two faint galaxies in the vicinity, which were both visible with indirect vision.
