Flexure updates to MOSFIRE on the Keck I telescope

摘要

We present a recent evaluation and updates applied to the Multi-Object Spectrometer For Infra-Red Exploration (MOSFIRE)1 on the Keck I telescope. Over the course of significantly long integrations, when MOSFIRE sits on one mask for ＞4 hours, a slight drift in mask stars has been measured. While this does not affect all science-cases done with MOSFIRE, the drift can smear out signal for observers whose science objective depends upon lengthy integrations. This effect was determined to be the possible result of three factors: the internal flexure compensation system (FCS), the guider camera flexure system, and/or the differential atmospheric refraction (DAR) corrections. In this work, we will summarize the three systems and walk through the current testing done to narrow down the possible culprit of this drift and highlight future testing to be done.