M. Riva, M. Landoni, F. M. Zerbi, D. Mégevand, A. Cabral, S. Cristiani, B. Delabre
Abstract
This paper presents the Espresso Front End mechanical and optical conguration. ESPRESSO, Echelle SPectro-graph for Rocky Exoplanets and Stable Spectroscopic Observations, will combine the efficiency of modern echelle spectrograph design with extreme radial-velocity precision. It will be installed on ESO's VLT and it is expected to achieve a gain of two magnitudes with respect to its predecessor HARPS. The instrumental radial-velocity precision will also be improved to reach cm/s level. The Front End is a modular subsystem that collects the light coming from the Coude Trains of all the Four Telescope Units (UT), provides Field and Pupil stabilization via piezoelectric tip tilt devices and inject the beam into the Spectrograph fiber. The Front End will also inject the calibration light coming from the calibration unit. There will be four Front End modules, one per UT. A rotary Stage will provide the toggling between different observation mode: Single UT Ultra High resolution (SUT-UHR), Single UT High resolution (SUT-HR) and multiple UTS Mid Rsolution (MUT-MR). The field and pupil guiding is obtained through a reimaging system that elaborates the halo of the light out of the Injection Fiber and a telescope pupil beacon. A dedicated guiding algorithm has been studied in order to provide proper image stability even with faint objects (mv=20).
Keywords
Calibration - Exoplanets - Optomechanical: design - Spectrographs - Telescopes
Notes
ISBN: 9780819491473
Ground-based and Airborne Instrumentation for Astronomy IV
I. S. McLean, S. K. Ramsay, H. Takami
SPIE
Volume 84469, Number 8446, Page 84469E_1
2012 September
