Conceptual Design Of The Mobie Imaging Spectrograph For Tmt

The Multi-Object Broadband Imaging Echellette (MOBIE) is the seeing-limited, visible-wavelength imaging multi-object spectrograph (MOS) planned for first-light use on the Thirty Meter Telescope (TMT). The MOBIE project to date has been a collaboration lead by UC Observatories (CA), and including the UH Institute for Astronomy (HI), and the NAOJ (Tokyo, Japan). The current MOBIE optical design provides two color channels, spanning the 310-550nm and 550-1000nm passbands, and a combination of reflection gratings, prisms, and mirrors to enable direct imaging and three spectroscopic modes with resolutions (lambda/Delta lambda) of roughly 1000, 3000, and 8000 in both color channels, across a field of view that ranges from roughly 8x3 arcmin to 3x3 arcmin, depending on resolution mode. The conceptual design phase for the MOBIE instrument has been underway since 2008 and is expected to end in 2015. We report here on developments since 2010, including assembly of the current project team, instrument and camera optical designs, instrument control systems, atmospheric dispersion corrector, slit-mask exchange systems, collimator, dichroic and fold optics, dispersing and cross-dispersing optics, refracting cameras, shutters, filter exchange systems, science detector systems, and instrument structures.