Quasar 0957+561A/B

(Click on the picture above to go to the main image.)

This "double" quasar is the first example found that demonstrates Einstein's prediction of gravitational lensing. This is a single quasar that has two nearly identical images caused by the gravitational effect of an (unseen) intervening galaxy. Scientists are measuring the time delay in the arrival of fluctuations in both images of the quasar. These fluctuations arrive about a year apart. This allows the scientists to measure the geometry of space between us and the quasar.

I normally take a quick 30 second picture of an object to ensure that its positioning, etc. are correct. In this case, although the background star field was what I expected, there was no sign of the quasar! It was only when I had taken the 15 minute exposure that I actual saw the quasar.

The quasar is the pair of small faint "stars" just left of center.

I took this picture from my driveway.

Also see the Hubble Space Telescope image in which you can see the intervening galaxy.

Constellation	Ursa Major
Right Asc (hh:mm:ss)	10:01:00
Declination(deg:sec)	55:56
Magnitude	15
Size (ArcMin)	1
Tirion SkyAtlas 2000	#2
Uranometria 2000	#45