Design updates and status of the fourth generation TripleSpec spectrograph

Abstract

TripleSpec 4 (TS4) is a near-infrared (0.8um to 2.45um) moderate resolution (R ~ 3200) cross-dispersed spectrograph for the 4m Blanco Telescope that simultaneously measures the Y, J, H and K bands for objects reimaged within its slit. TS4 is being built by Cornell University and NOAO with scheduled commissioning in 2015. TS4 is a near replica of the previous TripleSpec designs for Apache Point Observatory's ARC 3.5m, Palomar 5m and Keck 10m telescopes, but includes adjustments and improvements to the slit, fore-optics, coatings and the detector. We discuss the changes to the TripleSpec design as well as the fabrication status and expected sensitivity of TS4.