Ground-based and Airborne Instrumentation for Astronomy III
DOI: 10.1117/12.856487
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The detection of Earth analogues requires extreme Doppler precision and long term stability in order to measure tiny reflex velocities in the host star. The PSF from the spectrometer should be slowly varying with temperature and pressure changes. However, variations in the illumination of the slit and of the spectrograph optics occur on time scales of seconds, primarily because of guiding errors, but also on timescales of minutes, because of changes in the focus or seeing. These variations yield differences in the PSF from observation to observation, which are currently limiting the Doppler precision. Here, we present the design of a low cost fiber optic feed, FINDS, used to stabilize the PSF of the Hamilton spectrograph of Lick observatory along with the first measurements that show dramatic improvement in stability.