SPACE.com -- Powerful New Cameras Will Be Needed for Gigantic Next Generation Telescopes

Detector cooler for seeing hot X-rays: Observing faint celestial X-ray sources require an extremely efficient detector system. A new detector, called an X-ray microcalorimeter, works by sensing the heat pulses generated by X-ray particles w hen they are a

Spiderweb for capturing Big Bang echos: Nickanamed 'Spiderweb' this detector is used to look at the faint afterglow from the big bang. Suspended on the web is a superconducting thermometer for measuring minute changes in the temperature of t his afterglow

An artist's rendition of the Chandra X-ray observatory


	Powerful New Cameras Will Be Needed for Gigantic Next Generation Telescopes By Ray Villard Special to SPACE.com posted: 10:56 am ET 12 July 2000

Astronomers are looking ahead to a new generation of powerful space telescopes needed to penetrate ever deeper into the universe to seek out planets, the nature of dark matter, galaxies on the edge of space and time, among many other research areas

Astronomers are looking ahead to a new generation of powerful space telescopes needed to penetrate ever deeper into the universe. They will seek out extrasolar planets, the nature of dark matter and galaxies on the edge of space and time, among many other cosmological phenomena. Some of these behemoths will have mirrors the size of a large backyard swimming pool, or have a number of smaller mirrors precisely linked together optically to act as one giant mirror.

"Its hard to imagine what kind of things we will discover when we make that great leap in capability. The larger possibilities mean well make discoveries we havent event thought of yet."

But even with all the light-gathering power of these new super-telescopes, they will only be as good as the quality of the pictures they can take. So, scientists and engineers are at work on an equally powerful new generation of cameras that can be affixed to the telescopes to yield faster, sharper and wide full-color views of the wonders of the cosmos. This will drive advances in sold-state physics, silicon-crystal growth, cryogenics, superconductivity, and data processing.

"Our science goals in the coming decades will require extraordinary and unprecedented detector arrays," said Craig McCreight of the NASA Ames Research Center. "This is a period of feverish creativity," added Paul Richards of the University of California at Berkeley, "The speed at which we can make astronomical observations is doubling every eight months."

As the numbers of pixels in a CCD increases, so does the sharpness of the image. In these three images of Jupiter, the number of pixels in the detector quadruples in each consecutive picture from left to right.

The light from todays telescopes is typically focused onto a detector called a Charge-Coupled Device (CCD) which is commonly used in home video cameras and consumer digital cameras. A CCD is a postage-stamp-sized slice of silicon subdivided into a "porch screen" mesh of many thousands of microscopic cells called pixels (picture elements), which convert the incoming light into digital signals for computer processing and display. The more pixels, the sharper the image.

Most present-day CCDs used in astronomy are equivalent to using grainy, black-and-white photographic film in a snapshot camera. And, the sky view is narrow due to the detectors small area. The new bigger and more efficient detectors envisioned will be the equivalent of having ultra-sharp high-fidelity color film in "jumbo picture" format.

Combined with the raw light-collecting power of a big mirror, the new detectors promise to allow astronomers to see the first stars ever born, probe the environment around a black hole, trace the grand cosmic "web" of gas that is an underlying structure of our universe.

Anticipating the combined giant optics and powerful cameras, astronomers freely talk in terms of millionfold improvements over the way they view the universe now. "Its hard to imagine what kind of things we will discover when we make that great leap in capability," said Macia Rieke of the University of Arizona. "The larger possibilities mean well make discoveries we havent event thought of yet."

For example, by combining the new detectors with mirrors two to three times the size of Hubble Space Telescope, "We could achieve first color images of terrestrial planets," said Jon Morse of the University of Colorado. Morse said that such a telescope could take on 1,000 deep views of the universe in the same time it takes Hubble telescope to make just one picture, and could do it with resolution that is 15 times greater than Hubbles.

Next-generation detectors being developed in a collaboration between astronomers and aerospace industry will have over a billion picture elements rather that the few million elements available on the largest chips today. To get an even wider view of the heavens -- a thousand times greater than the first generation of space telescopes -- astronomers plan not only to build bigger CCDs, but to "mosaic" them together, going from a detector the size of a thumbnail to one the size of a dinner plate. "Its like going from a single ceiling tile to covering the whole ceiling with tiles," said McCreight.

To work efficiently, CCDs and other solid-state detectors will be chilled to almost absolute zero (minus 460 degrees Fahrenheit or minus 273 Celsius). This will allow them to precisely measure the energy of incoming particles of light, called photons, and convert them to color values. Making color pictures today is laborious because separate images must be taken through different color filters and then combined. Instead, important color information will be captured in a single exposure, vastly increasing the speed and accuracy of space observations.

Advanced optical space telescope: This is a proposed giant optical-ultraviolet space telescope with a mirror three times the diameter of the Hubble Space Telescope's (HST). It will be able to make deep observations of the heavens in a fraction the time required by HST.

The resulting barrage of data from these super-chips will require high-speed computers capable of crunching and displaying gigabytes of data from a single astronomical exposure.

The new detector technology is not limited to visible wavelengths, but also see from the far infrared to X-rays. "For the first time, we can look at the universe in detail across a broad range of energies," said Morse. "This is needed to fully understand a host of astronomical phenomena."

"There is an exciting range of space observatories over coming decades," added astronomer Phil Crane of NASA Headquarters. "Sensor technology is important in all areas to improve the performance and amount of data returned from all these missions."

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