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.