MARTINI: sensing and control system design

摘要

Abstract: The multiple aperture real-time image normalization instrument (MARTINI) is an astronomical adaptive optics system for visible imaging and spectroscopic feedthrough at the 4.2 m William Herschel Telescope (WHT) on La Palma. It consists of a six-subaperture, tip-tilt-piston, segmented mirror device and uses 4r$-0$/ aperture-matching to provide optimum slope removal in zones large enough for operation in the visible and with reference objects fainter than V $EQ 13$+m$/. This limit is achieved by optimizing the use of reference light, by analyzing the information from a photon counting wavefront sensor using a nonframing (i.e., irregular sampling) infinite impulse response filter for estimation and prediction of the wavefront slopes. The value of this approach is discussed along with its extension to higher-order correction schemes. Experimental evidence supporting the theoretical basis of the MARTINI system, including 4r$-0$/ matching and the form of turbulence power spectra is also presented. The astronomical potential of such an approach, and the drawbacks, are outlined. !3