A new type of light sensor for use by the world's largest telescopes promises to reveal objects never before seen or glimpsed only poorly.
The sensor, shown above and developed by a team led by Stephen Holland at the Lawrence Berkeley National Laboratory in California, is known as a high-resistivity (or Hi-Rho) CCD, and it is particularly effective at detecting a region of the light spectrum that eludes most current
| What is a CCD? |
| A CCD (Charge-Coupled Device) is an electronic sensor that can detect and record patterns of light in a way similar to photographic film. But for astronomy, CCDs have several advantages over film. Want to know more? |
Arne Henden, senior research scientist at the U.S. Naval Observatory in Flagstaff, Arizona, said most of this range of light has been largely unexplored, even though it passes relatively well through the screen of our atmosphere.
"Very red objects such as brown dwarfs, or highly obscured objects such as extremely young stars (where longer wavelengths can pass through the dust), are more easily observed [with the new sensor]," Henden said. (Brown dwarfs are tiny stars that are thought to be quite common, but because they emit mostly infrared light they are very difficult to see with conventional sensors and cameras.)
The new sensor also could help answer the deepest questions in cosmology, such as the shape and geometry of the universe. Don Groom, a collaborator in the development of the new sensor and member of the Supernova Cosmology Project, said the new device "enables effective observation of objects reddened by the cosmological redshift (these are objects at the remotest reaches of the universe) or by obscuring dust."
"For example," Groom said, "the reach of the Supernova Cosmology Project in discovering and observing very distant supernovae can now be very much extended, permitting sensitive measurements of the geometry of the universe and checks on our previous discoveries."
Because the new sensors are easier to make and can be joined side by side to make very large sensor arrays, astronomers will be able to equip their telescopes with the new sensors at a lower cost. That will increase the number of telescopes that can peer deeper into space.
The Hi-Rho CCDs may also find uses in other fields, such as medical imaging, possibly opening new venues in medical diagnosis and medical monitoring.
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