MIT Technology Review has an interesting article on the latest technology in telescopes that will be able to photograph the entire sky simultaneously and continuously.
One problem with telescopes is that they can only peer at a tiny piece of sky at any one time. Astronomers have attempted to get around this by combining many images, each just a few degrees wide, that cover different areas of the sky. These state-of-the-art systems can produce a map of the entire sky every day.
But astronomers very well know that many interesting events occur on much shorter timescales, such as the transit of exoplanets across other stars, binary stars that eclipse, gamma ray bursts and so on. Capturing the changes associated with these events requires a much more rapid way of photographing the entire sky.
Today, Nicholas Law and pals at the University of North Carolina at Chapel Hill, say they are developing just such a piece of kit. Their new gigapixel-scale telescope will be capable of photographing the entire sky simultaneously and continuously at relatively low cost. Indeed, this instrument represents an entirely new type of telescope which Law and co call the Evryscope, from the Greek for ‘wide-seeing’.
The design is straightforward in principle. It consists of 23 small telescopes mounted on a hemispherical dome that can rotate to track the sky. Each small telescope has a 7 cm aperture and a field of view of a few hundred square degrees. Each one focuses light onto 29 megapixel chip.
The dome is designed so that the fields of view of each of the small telescopes overlap to cover around 10,000 square degrees of sky simultaneously and to produce 0.7 gigapixel images. The dome rotates on equatorial mount so that the Evryscope can record exposures of up to 3 hours before ratcheting back and tracking the next sky area.
That will produce 700 megapixel images every two minutes at a data rate of 5 MB per second. This will be stored on a 20 TB storage unit that should help to handle three months of data, assuming that the weather will be good two thirds of the time.