A popular part of the hobby of astronomy today is snapping photos of the night sky and all its wonders—a few keeners even bag new supernovae, comets, and asteroids too. At the heart of these discoveries, both for amateurs and professionals, are digital cameras, also known as CCD imagers. While even the most basic consumer-level cameras can offer stunning results, when it comes to telescopes and camera sizes used by stargazers, the bigger, the better.
That’s why when earlier this week astronomers announced the detection of a new, distant comet, it was a noteworthy find for astrophotographers. While the discovery telescope—located on the summit of Hawaii’s Haleakala mountaintop—is not considered that large by today’s professionals, what made this find possible is its digital eye, a true giant among giants.
The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) is equipped with the world’s largest digital camera, delivering staggering 1,380 megapixels—nearly 1.4 gigapixels on a CCD array measuring 40 centimeters across (above). Put that into context: A typical store-bought digital camera contains just 12 million pixels (12 megapixels) with the CCD chip measuring just a few millimeters across!
The Pan-STARRS cam has a mosaic of 60 CCD individual cells, each having 4,800 by 4,800 pixels arranged in an 8 by 8 array. It’s able to image an area of sky equivalent to 7 square-degrees—that’s an incredible chunk of celestial real estate that would swallow up 36 moon disks in the sky.
This monster shooter, which went online in 2009, allows astronomers to hunt for 99 percent of Earth-crossing asteroids down to 300 meters across using digital images that can go 100 times fainter than any previous survey.
It’s hard to imagine that astronomers can best this beast, but plans are well underway in Chile for the 8.4-meter Large Synoptic Survey Telescope (LSST), which will be equipped with an even larger sensor system (3.2 billion pixels, or 3.2 gigapixels). The system will stretch 63 centimeters across and sport a ten square-degree field of view. LSST will survey the entire visible sky at multiple wavelengths every week when it sees first light in late 2015.