Gravitational lensing is defined as the bending of light from a distant light source by a massive foreground object. The amount of bending is one of the predictions of Albert Einstein's general theory of relativity.

The most visible example of gravitational lensing for us to see is when the light from a galaxy many billions of light years away is bent by a massive foreground galaxy cluster, typically located about half as far away. The lensing usually appears as thin curving arcs of light surrounding the galaxy cluster.

The Hubble can capture gravitational lensing without much of a sweat. But from our backyards here on earth, it is not so easy to capture lensing because of atmospheric disturbance, the distances involved, the faintness of the arcs, and particularly the thinness of the arcs. A combination of excellent seeing, a powerful telescope, and lots of integration time is required. Even then, it is a challenging task. This is my fourth attempt – the previous 3 were not successful, at least not definitively to my eyes.

At the very center of my image is the Cheshire Cat galaxy cluster. It is about 4.5 billion light years away. The cluster is dominated by two closely spaced elliptical galaxies (SDSS J103843.58+484917.7 and SDSS J103842.68+484920.2), looking like the cat’s “eyes”. A smaller galaxy is seen between these 2 galaxies (the cat’s “nose”). This cluster is 12 arc-seconds wide in my image, about the same apparent width to us as the planet Venus.

This Cheshire Cat galaxy cluster is lensing four separate background galaxies with redshifts ranging from 0.80 to 2.78, which corresponds to light travel distances which range from 7 to 11 billion light years from us. The lensed galaxies appear as faint arcs of light. The gravitational lensing arcs are clearly seen in the Hubble picture mouseover image (Revision K). The Hubble image also clearly shows why this object is called the Cheshire Cat galaxy cluster.

So, are the lensing arcs visible in my image? Although it is poorly defined, I can definitely see one of the arcs slightly above and to the right of the cluster. The other arcs are tougher for me to see. I will try to gather additional quality data in the coming seasons to better define the arcs in the image. But for now, I am happy to be able to capture a galaxy 10 billion light years away, even if it only show up as a poorly defined faint arc of light.