Advanced Imaging


Advanced Imaging Magazine

Updated: July 8th, 2008 05:26 PM CDT

Navigating the Maze of Cameras & Sensors for Scientific Applications

e2v's CCD91-72s, which employs a 4.5 x 6.0 cm CCD, will help the European Space Agency's Gaia catalog one billion stars in our galaxy when it's launched in 2011.
Part of the Gaia CCD and Focal Plane Technology Demonstrators program, this back-illuminated, astrometric field demonstrator CCD-complete with flex circuit-in a custom-handling jig.
The SuperWASP-North observatory, part of the Wide Angle Search for Planets project, is located on the island of Santa Cruz de la Palma in the Canary Islands.

By Lee J. Nelson
Contributing Editor

JWST is expected to help find the Universe's first galaxies, essentially linking the Big Bang to our own Milky Way. Peering through dusty clouds, on-board instruments primarily will sense in the infrared region of the electromagnetic spectrum with some visible-range capability.

As the principal imager, the Near Infrared Camera (NIRCam) will address many of JWST's core science goals: detecting early phases of galaxy and star formation and distant supernovŠ; galaxy morphology and color at very high red-shift in rest-frame optical wavelengths; mapping dark matter via gravitational lensing; and, studying stellar populations in nearby galaxies.

NIRCam consists of two broad- and intermediate-band imaging units, each with a 2.16×2.16 arcmin field-of-view. The modules have short and long wavelength channels to capture images simultaneously with light split by a dichroic plate at ∼2.35 μm. Short wavelengths are sampled at 0.0317 arcsecs/pixel (4096×4096 pixels) and the long channels are read at 0.0648 arcsecs/pixel (2048×2048 pixels). Each imager has a pupil wheel with extra optics and analyzers for wavefront sensing, a capability which ensures complete redundancy since mission success will depend upon their flawless operation.

The anticipated point-source sensitivity is ∼3.5 nanoJansky for 0.6<λ<5.0 μm over a 100,000-second exposure with a signal-to-noise ratio of 10. All 10 detectors are mercury/cadmium/telluride 2048×2048 arrays (Teledyne Scientific & Imaging, LLC, Thousand Oaks, Ca.). Led by a team at the University of Arizona (Tucson), NIRCam currently is under construction and receives additional support from Lockheed-Martin's Advanced Technology Center (Palo Alto, Ca).

Contributing editor and industry analyst, Lee J. Nelson, is at the forefront of emerging as well as evolving technologies for compute-intensive electronic imaging applications. Contact him at 1-703-893-0744, or

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