A galaxy 11 billion light years away? Photographed by an Ottawa amateur astronomer? In his back yard observatory?
Let me start with some background.
Last June, we introduced you to the local chapter of the Royal Astronomical Society of Canada (RASC). They’re a group of amateur astronomers who enlighten audiences about the wonders of astronomy at monthly public meetings.
One audience favourite at Ottawa RASC meetings is astrophotography by local amateur astronomers. The RASC encourages experienced photographers and beginners to present samples of their craft.
Digital photography has revolutionized astrophotography. Beginners achieve lovely images with much less effort than with film. Experienced astrophotographers push the envelope, often producing results that used to need large professional telescopes in remote locations or on satellites.
At the November meeting, one local veteran RASC astronomer, Paul Klauninger, presented his image that includes galaxies that are 11, 10.5 and 7.2 billion light years away. He took this image with his own 280mm (11-inch) wide telescope.
To capture these galaxies on his small scope, he needed the help of an extra lens: a very big lens!
The photo is of a cluster of over 10,000 galaxies (known as Abell 2218) that is 2.3 billion light years away.
As Einstein theorized, mass warps the fabric of space/time. Light travels the shortest distance between two points. In the presence of mass, that shortest distance follows the warped space around that mass. The larger the mass, the greater the warp. The gravity of this cluster warps space/time and magnifies far away objects, making it possible to capture light from far galaxies behind Abell 2218. Klauninger has managed to image four of them.
If this sounds like something that would need the Hubble telescope, a Hubble image of Abell 2218 taken in year 2000 inspired Klauninger to try to achieve a similar result on his own. But Klauninger used a 28 cm. telescope in his back yard instead of a 2.4 metre telescope in space.
Not only does Klauninger present his image, side by side with the original NASA Hubble image, he also explains:
- what galaxy clusters are,
- some of the history of how they were discovered,
- how galaxy clusters are the large scale building blocks of the universe,
- the cosmic web of galaxies within a few billion light years of earth,
- how dark matter makes up most of the mass of these clusters,
- how gravitational lensing happens,
- where Abell 2218 is located in the night sky, and
- the steps he followed to get to his image.
Klauninger worked on this image from February to September this year. It is effectively a merger of 7 hours of digital photos each with 10 to 20 minute exposures. He actually accumulated 25 hours of exposures and selected the best 7 hours.
His talk is available online, for free, as part of the video RASCNOVEMBER2016-A on Ustream starting at minute 20:50. Klauninger’s talk is titled “Abell Cluster Images”.
If you just want to see Klauninger’s image, you can fast forward to minute 47:36 on the video.
(Note: these times may differ depending on your device. They are accurate to a few seconds for Safari and Firefox on a Mac, but they are a few minutes off on an iPhone.)
Monthly meetings of the Ottawa RASC usually take place on the first Friday of the month. Find more details at RASC Ottawa Centre Meetings.