Quasar: QO957+561 A/B (March 30, 2018)

This is an image of the so-called "Twin Quasar."  The two dots near the center upper-half of the image are light from a quasar, a galaxy that is very far away,  The upper dot is called A and the lower one B. The light from B is combined with that of a galaxy that appears so close to B that my telescope cannot distinguish between the two.  But astronomers with larger telescopes have taken spectra of these light sources and discovered that they are very distant.

They are so far away that the expansion of the universe has red-shifted their spectra.  The two dots A and B have a red-shift measured at 1.41, and the galaxy that appears near B is red-shifted 0.355.  Astronomers have found a galaxy cluster in the line of sight at a red-shift of around 0.5.  We can translate these measurements into light years.  The light from quasar components A and B has been traveling 8.7 billion years.  The light from the galaxy appearing next to B left its source 3.7 billion years ago.  The galaxy cluster in the area produced the cluster's light around 5 billion years ago.  My image shows only A and B, not the galaxies in between us and them.  But a nice Hubble Telescope image here shows the galaxy near B and the background cluster.

This is a record for me.  I've never recorded light as old as 8.7 billion years!

What is even more remarkable, the galaxy and cluster between us and A and B acts as a gravitational lens.  A and B are actually a single light source! We see them as two because the strong gravity of the galaxy and cluster in between acts as a lens, bending the light from the far-away quasar into what we see as two images, A and B.  This is proof that gravity bends light, and it is a predicted effect of the theory of relativity.  The Twin Quasar was the first gravitational lens discovered, in 1979, and it is the first one I have imaged.

This image is 21x480" with the SXVF-H9C through the CFF Classical Cassegrain at f/8.1.  As always, the telescope performed wonderfully.  This image was taken under a nearly full moon.  The Twin Quasar is in western Ursa Major, however, so quite far from the full moon in late March.

I relied on this paper in writing this brief summary.