Multi-Object Double Spectrographs (MODS)
The Multi-Object Double Spectrographs (MODS) are two identical high-throughput optical dichroic-split double-beam low- to medium-dispersion CCD spectrometers deployed at the Large Binocular Telescope (LBT). They operate in the 320-1050nm range at a resolution of R=2000. MODS1 saw first-light at the LBT in September 2010, finished primary commissioning in May 2011, and began regular science operations in September 2011. MODS2 was delivered to the LBT in late 2013 and began binocular science operations with MODS1 at the end of 2014. The MODS continue in operation as one of the most used and productive facility instruments at the LBT.
Instrument Specification
- Project type: Facility Instrument - multi-object spectrograph
- Wavelength: 320-1050nm (2 channels with dichroic)
- Resolution: gratings: R~2000; double-pass prisms: (R=500-150)
- Field of View: 6x6-arcmin
- Mode/Modes: seeing-limited low/mid resolution long-slit and multi-object spectroscopy, direct imaging
- Primary science: extragalactic, stellar, and solar system objects
- Telescope: Large Binocular Telescope, AZ, USA
- Years active: 2010 - present
- Reference: Pogge et al. 2012, SPIE, 8446, 0GP
Instrument Facts
- The workhorse facility optical spectrographs at the LBT.
- Use curved laser-cut slit masks for multi-object targets up to 25 slits in grating, ~50 in prism mode.
- MODS1+2 can use the same mask in both instruments (identical twining) or different masks (fraternal twinning).
- Combined MODS1+2 provides an effective 11.6-m aperture in identical twinning mode.
- An internal active flexure compensation system makes it stable across most of the sky for long integrations
- The largest instruments built by the ISL to date: 4.5m long, 2.5m diameter, and 3500kg each!
Instrument Team
Richard Pogge (PI)
Paul Martini (Project Scientist)
David Weinberg (Project Scientist)
Bruce Atwood (Instrument Scientist)
Tom O'Brien (Senior Mechanical Engineer)
Paul Byard (Optical Designer)
Ross Zhelem (Optical Designer)
Mark Derwent (Mechanical Engineer)
Ray Gonzalez (Software Systems Developers/Engineer)
Jerry Mason (Software Systems Developers/Engineer)
Daniel Pappalardo (Electrical Engineer)
Mark Johnson (Electrical Engineer)
S. Ralph Belville (Design Engineer)
Dave Brewer (Senior Instrument Maker)
Dave Steinbrecher (Senior Instrument Maker)
Ed Teiga (Electronics Technician)
Brandyn Ward (Electronics Technician)
Jason Eastman (Graduate Student)
Jennifer Marshall (Graduate Student)
Rebecca Stoll (Graduate Student)
Andy Krygier (Student Engineering Assistant)
Chris Colarosa (Student Engineering Assistant)
Justin Randles (Student Engineering Assistant)
Josh Rosenbeck (Student Engineering Assistant)
