KOSMOS and COSMOS: New facility instruments for the NOAO 4-meter telescopes

TL;DR

KOSMOS and COSMOS are new high-efficiency imaging spectrographs for the NOAO 4-meter telescopes, enabling versatile imaging and spectroscopy with high spectral resolution and broad wavelength coverage.

Contribution

This paper introduces the design, construction, and performance of nearly identical, upgraded spectrographs for the Mayall and Blanco telescopes, expanding observational capabilities.

Findings

High efficiency in imaging and spectroscopy

Versatile use with different CCDs and modes

Successful commissioning at both telescopes

Abstract

We describe the design, construction and measured performance of the Kitt Peak Ohio State Multi-Object Spectrograph (KOSMOS) for the 4-m Mayall telescope and the Cerro Tololo Ohio State Multi-Object Spectrograph (COSMOS) for the 4-m Blanco telescope. These nearly identical imaging spectrographs are modified versions of the OSMOS instrument; they provide a pair of new, high-efficiency instruments to the NOAO user community. KOSMOS and COSMOS may be used for imaging, long-slit, and multi-slit spectroscopy over a 100 square arcminute field of view with a pixel scale of 0.29 arcseconds. Each contains two VPH grisms that provide R~2500 with a one arcsecond slit and their wavelengths of peak diffraction efficiency are approximately 510nm and 750nm. Both may also be used with either a thin, blue-optimized CCD from e2v or a thick, fully depleted, red-optimized CCD from LBNL. These instruments were developed in response to the ReSTAR process. KOSMOS was commissioned in 2013B and COSMOS was commissioned in 2014A.