We present the design of SCALES (Slicer Combined with Array of Lenslets for Exoplanet Spectroscopy) a new 2-5 micron coronagraphic integral field spectrograph under construction for Keck Observatory. SCALES enables low-resolution (R∼50) spectroscopy, as well as medium-resolution (R∼4,000) spectroscopy with the goal of discovering and characterizing cold exoplanets that are brightest in the thermal infrared. Additionally, SCALES has a 12x12" field-of-view imager that will be used for general adaptive optics science at Keck. We present SCALES's specifications, its science case, its overall design, and simulations of its expected performance. Additionally, we present progress on procuring, fabricating and testing long lead-time components.
The Wide Field Optical Spectrograph (WFOS) is one of the first-light instruments of Thirty Meter Telescope. It is a medium resolution, multi object, wide field optical spectrograph. Since 2005 the conceptual design of the instrument has focused on a slit-mask based, grating exchange design that will be mounted at the Nasmyth focus of TMT. Based on the experience with ESI, MOSFIRE and DEIMOS for Keck we know flexure related image motion will be a major problem with such a spectrograph and a compensation system is required to mitigate these effects.We have developed a Flexure Compensation and Simulation (FCS) tool for TMT-WFOS that provides an interface to accurately simulate the effects of instrument flexure at the WFOS detector plane (e.g image shifts) using perturbation of key optical elements and also derive corrective motions to compensate the image shifts caused by instrument flexure. We are currently using the tool to do mote-carlo simulations to validate the optical design of a slit-mask concept we call Xchange-WFOS, and to optimize the flexure compensation strategy. We intend to use the tool later in the design process to predict the actual flexure by replacing the randomized inputs with the signed displacement and rotations of each element predicted by global Finite Element Analysis (FEA) model on the instrument.
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