Taking a picture of the most luminous blazar flare ever recorded.

A blazar is an active galactic nucleus with a relativistic jet (a jet composed of ionized matter traveling at nearly the speed of light) directed towards the observer.

CTA 102 is a blazar-type quasar discovered in the early 1960s in the constellation Pegasus. It is also one of the two great false alarms in the search for extra-terrestrial life, as in 1963 its radio signature was proposed as evidence of extraterrestrial civilization, causing a worldwide sensation in popular media. The identification was soon rejected and the radio source reclassified as a quasar. American band “the Byrds” celebrated this episode in their song “C.T.A.-102” from their 1967 album “Younger Than Yesterday”.

With a redshift of z(spectroscopic)=1.032 and a distance of of 8 billions years, it is a very distant object. Glowing around Magnitude 17, it is also a faint object.

There is a thread on Cloudy Night regarding the most distant object amateurs have observed. The most popular object seems to be 3C 273, with z=0.158, 2.4 billion years away and a Magnitude of 12. So 3 times closer and much brighter than CTA 102.

In December 2016, I heard the news that CTA 102 was experiencing a flare (in fact the most luminous blazar flare ever recorded). It had brightened to Magnitude 11, and was visible in the Northern Sky in the evening. So I decided to give it a shot.

Given the announced magnitude, I felt I could save a trip to the dark site and set up in my light polluted back yard. After putting the gear in station, I plate solve to the location in Pegasus and started imaging with the C11 at f/8 (with the focal reducer).

After stacking and processing the frames to remove some of the light pollution, NGC 7305 was clearly identifiable, and CTA 102 was just to the East of it, very bright. I plate-solved again in Pixinsight and labeled the image to confirm the identification.

This is my most distant object photographed so far, at 8 billion light years, and it will likely stay so for some time. The light collected by the C11 was emitted when the universe was 5.8 billions years old, versus 13.8 billion years today.

For reference, the earth’s age is 4.5 billion years.

Leave a Reply

%d bloggers like this: