Design and Development of Henrietta, a high-precision ground-based NIR spectrograph to detect exoplanet atmospheres.

Henrietta is a near-infrared (NIR) long-slit/multi-object cryogenic spectrograph to be deployed at the 1-m Swope Telescope at Las Campanas Observatory. Henrietta is designed to survey the molecular content of exoplanet atmospheres from .97 – 1.8 microns at a resolution of 200. The primary driver of Henrietta is the noticeable gap in ground-based spectrophotometric precision from the optical to the infrared and the need for high precision spectrophotometric follow ups relevant to JWST. I will discuss how Henrietta seeks to resolve this gap and achieve near photon-noise limited observations by mitigating three insidious sources of noise and systematics: atmospheric scintillation, NIR sky emission, and subpixel quantum-efficiency fluctuations in H2RG arrays. Henrietta will have first light in August of 2022 and if it reaches its design goal it will enable the robust detection of exoatmospheres from the ground, become a ‘finder scope’ for JWST, and act as a testbed for future instruments to achieve high spectrophotometric precision from the ground.