Going Deep… 7.8 Billion Years Deep!
Gravitational lensing occurs when light bends through space due to the gravity of another body. In the first verified case of gravitational lensing (nearly 30 years ago), a mega distant quasar is lensed by an entire galaxy sitting virtually “in line of site” with us. The light from this quasar is bent as it passes the galaxy and is split into two distinct, separate images. Known as the Double Quasar, or Twin Quasar, QSO 0957+561 is located in Ursa Major where it shines near magnitude 17 – well out of visual observation for the typical amateur. This quasar has a redshift value of “z=1.414″ (curiousity: √2 ~= 1.414), and is flying away from us at 70% of the speed of light. This places it’s distance nearly at twice as old as our planet, eight billion years.
However, with long-duration photography, one can push the limits of equipment and actually bring life to this object – which is easily the most distant thing I’ve ever been lucky enough to image. Back on February 2, despite mediocre 2/5 seeing, and a very modestly sized four inch refractor (NP101is!), I was able to pull enough photons to illuminate my CCD. While I wasn’t able to resolve the two images as distinct light sources, it is elongated enough to where a little imagination will go along ways (8 billion light years is pretty far).
To pull this off I had to take the longest exposures I’ve ever done – 20 minutes a whack. That means for 20 minutes, no airplanes, no wind, rock solid autoguiding, awesome polar alignment, no temperature focal shift, no earthquakes, and nobody sneezing nearby. Obviously the Celestron CGEM mount was up to task: fairly gentle processing (stretching) and blammo — there it is. As an added bonus, on-edge galaxy NGC 3079′s axis points right to it. NGC 3073 is to the right side, the 1×1 arc minute fuzzball. There are actually a few quasars in this image — can you find any others?