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sâmbătă, 22 septembrie 2012

Large Monolithic Imager sees first light on the Discovery Channel Telescope

The Large Monolithic Imager (LMI), a camera built at Lowell Observatory and funded by the National Science Foundation (NSF), recently took a set of first-light images on Lowell's 4.3-m Discovery Channel Telescope (DCT).

At the heart of the LMI is the largest charge-coupled device (CCD) that can be built using current fabrication techniques and the first of its kind to be made by e2v.

The 36-megapixel CCD's active surface is 3.7 inches on a side. The LMI's ability to provide much more accurate measurements of the faint light around galaxies separates it from cameras that use a mosaic of CCDs to produce images.

The attached first-light image is of NGC 891, an edge-on spiral galaxy about 30 million light-years away in the Andromeda constellation.

The image was obtained by Lowell's Phil Massey, Ted Dunham, and Mike Sweaton, and then turned into a beautiful color composite by Kathryn Neugent. The exposure consisted of 10x1 min (B), 5x1 min (V), and 6x1 min (R), all unguided.

In the coming months, astronomers from Lowell and its DCT institutional partners - Boston University, the University of Maryland, and the University of Toledo - will be getting many more images like this as the Telescope's commissioning continues.

Science contact: Phil Massey, Astronomer and LMI Principal Investigator, Lowell Observatory, 928-233-3264, phil.massey[at]lowell.edu

Science contact (alternative): Deidre Hunter, Astronomer, Deputy Director for Science and LMI co-Investigator, Lowell Observatory, 928-233-3225, deidre.hunter[at]lowell.edu

Media contact: Chuck Wendt, Deputy Director for Advancement, Lowell Observatory, 928-233-3201, cwendt[at]lowell.edu

The Large Monolithic Imager (LMI)

Built at Lowell Observatory and funded by the National Science Foundation (NSF), the LMI is an all-purpose optical imager featuring a 36-megapixel CCD with a field of view nearly 13 arcminutes by 13 arcminutes.

The LMI uses a single chip, which permits more efficient use of observing time (by not dithering), and far less reduction time, resulting in higher scientific throughput.

The LMI will serve as the principal imager and workhorse instrument for the DCT, enabling studies from solar system to extragalactic objects.

The instrument will allow the determination of the physical properties of comets and also provide the means of investigating the mass-luminosity relationship for both the highest and lowest mass stars. The LMI also sets a precedent for wide-field imaging with monolithic cameras, as well as for more efficient future mosaics.

To maximize the field of view, the LMI is mounted at the straight-through position of the DCT's Ritchey-Chretien instrument cube.

The LMI CCD is a 6.1Kx6.1K 15-micron device produced by e2v, their first, with a high DQE 4-layer AR coating. The special coating makes the chip very sensitive over the entire visible spectrum, from the near ultraviolet to the near infrared.

The LMI contains 18 filters, including broad-band and specialized interference filters.

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