A Multi-Object Double Spectrograph
for the Large Binocular Telescope

	MODS1 structure with mechanisms being fitted and prepped for IMCS testing in the OSU Astronomy shop - 2005 Nov 9 (Photo by Rick Pogge) [more pictures]	MODS on its Handling Cart (AutoCAD Rendering by Mark Derwent)

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MODS is a low- to medium-resolution Multi-Object Double CCD Spectrograph and Imager being designed and built by OSU for the Large Binocular Telescope. Two full MODS spectrographs will be built, one for each of the direct f/15 Gregorian foci of the LBT. The two MODS will work in tandem to exploit the full 11.8-meter effective aperture of the twin LBT mirrors.

MODS will provide low- and medium-resolution spectroscopy (R=2000-8000) and imaging across the entire 330-1100nm band in a 6x6-arcminute field of view. Multi-object spectroscopy is accomplished using custom-machined focal-plane slit masks fed into the beam by a 25-position mask cassette. A beam selector below the slit carries a dichroic that splits the incoming beam into separate red- and blue-optimized channels, each with its own collimator, grating, camera and detector, allowing simultaneous operation across the entire CCD band. The beam selector can also direct light into the red or blue channels alone, providing blue-/red-only modes to extend wavelength coverage across the dichroic notch as required.

The first two-channel MODS will be deployed at the SX Direct Gregorian Focus of the LBT in mid-2009, with the second two-channel MODS system deployed at the DX Direct Gregorian focus a little over a year later.

This web site provides links to documents, progress reports, and images detailing the status of the design and construction of the MODS spectrographs. The intended audience is the MODS project team, members of the LBT Optical Spectrograph Working Group (LBTOSWG), and interested members of the LBT community.

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Instrument Characteristics

Summary of Characteristics

Detailed Optical Specification

CCD Detectors

Gratings

Filters

Estimated Performance

Mechanical Systems

Design and Fabrication Images

Team MODS Progress Reports

External Project Reviews

Conceptual Design Review (1999 Mar 8-9)

Preliminary Design Review (2001 Sept 26)

LBTO Progress Review (2004 Apr 22-23)

Joint LBTO/TSIP Progress Review (2005 March 7-8)

Project Documents

Online Document Archive

Project Publications & Papers

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MODS Project Personnel and Vendors

Team MODS:

Project PI:Richard Pogge

Project Scientists: Paul Martini and David Weinberg

Instrument Scientist: Bruce Atwood

Sr. Mechanical Engineer: Tom O'Brien

Optical Designers: Paul Byard (ret.), Ross Zhelem

Mechanical Engineer: Mark Derwent

Software Systems Developers/Engineers: Ray Gonzalez & Jerry Mason

Electronics Engineers: Dan Pappalardo & Philip Covington (until Mar 2008)

Design Engineer: S. Ralph Belville (ret.)

Senior Instrument Maker: Dave Brewer

Instrument Maker: Dave Steinbrecher

Electronics Technician: Ed Teiga

Graduate Students: Jason Eastman, Jennifer Marshall

Student Engineering Assistants: Andy Krygier, Chris Colarosa, Justin Randles

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Our Sponsors:

MODS is supported by the Ohio State University with major support provided by grants from National Science Foundation's Division of Astronomical Sciences Advanced Technologies and Instrumention (AST-9987045) and NSF/NOAO TSIP Programs, and with matching funds provided by the Ohio State University Office of Research and the Ohio Board of Regents. Graduate students have been supported by the David G. Price Fellowship in Astronomical Instrumentation.