The largest digital image of our view of the night sky, which maps the
universe in more detail than any previous image, has been released by
scientists.

The international Sloan Digital Sky Survey-III
(SDSS-III) collaboration is releasing the image free to all, allowing
both professional astronomers and "citizen scientists" to use it to make
new discoveries.

The composite image has been put together over
the past decade from more than seven million 2.8 megapixel images,
creating a colour image of more than a trillion pixels.

This
terapixel image is so big and detailed that 500,000 high-definition
televisions would be needed to view it at its full resolution.

SDSS
data has already been used to discover nearly half a billion
astronomical objects, including asteroids, stars, galaxies and distant
quasars.

The image released on Tuesday was begun in 1998 using
what was then the world's largest digital camera, a 126-megapixel
imaging detector on the back of a dedicated 2.5m telescope at the Apache
Point Observatory in New Mexico, US.

During the past decade, the SDSS has scanned a third of the whole sky.

Using
the new image scientists will be able to measure distances to more than
a million galaxies detected in it, helping to provide data for a new
project to create a 3D map of the universe.

It is hoped this will help solve the mystery of so-called "dark energy" and how much of the universe is taken up by it.