Half a Million Galaxies, Yours to Explore

by Brian Ventrudo on December 10, 2009

This deep-field image from CFHT contains 500,000 galaxies.

Move over, Hubble Deep Field.  The Canada-France-Hawaii Telescope has released a new deep-field image of as many as 500,000 galaxies out to a distance of 7 billion light years.  And you can surf the entire image at high resolution with an interactive zoom feature at the CFHT website.

This new image is the result of the accumulation of several hundreds of hours of light integration over five years (2003-2008) with the CFHT using the 340 megapixel camera called MegaCam. This field and three more like it from other parts of the sky were systematically observed every three nights to detect faint supernovae going off in distant galaxies to study the effect of the mysterious dark energy responsible for the observed accelerating expansion of the universe.

Stacking these individual MegaCam images reveals a dense wallpaper of distant galaxies.  An observing technique called “dithering” allows coverage of a larger field of view than that of the camera itself, leading to a sky coverage over 370 megapixels. Approximately half a million galaxies can be counted on the entire image.

As it covers a full square degree of sky (about 5 times greater than the size of the full moon), the entire image is impressive enough.  But the ultra-high resolution of the image, along with a nifty interactive tool on the CFHT website, allows you to zoom in on tiny subsets of the image to see an astonishing assortment of galaxies out to a distance of 7 billion light years, about half-way to the edge of the observable universe.  A few foreground stars of our own galaxy are visible.  But almost everything else you see in this image is a distant galaxy.

You can access the image and the interactive viewer at the CFHT website.

Source: Canada-France-Hawaii Telescope

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