Site Map
Contacts
Follow us on Facebook Follow us on Twitter YouTube channel
Centro de Astrofísica da Universidade do Porto

ESPRESSO Coudé-Train: complexities of a simultaneous optical feeding from the four VLT unit telescopes

A. Cabral, M. Abreu, J. Coelho, R. Gomes, M. A. Monteiro, A. Oliveira, P. Santos, G. Avila, B. Delabre, M. Riva, P. Di Marcantonio, I. Coretti, N. C. Santos, F. M. Zerbi, D. Mégevand

Abstract
ESPRESSO is a fibre-fed, cross-dispersed, high-resolution, echelle spectrograph. Being the first purpose of ESPRESSO to develop a competitive and innovative high-resolution spectrograph to fully exploit the VLT (Very Large Telescope), and allow new science, it is important to develop the VLT array concept bearing in mind the need to obtain the highest stability, while preserving its best efficiency. This high-resolution ultra-stable spectrograph will be installed in the VLT at the Combined Coudé Laboratory (CCL), fed by four Coudé Trains, which brings the light from the Nasmyth platforms of the four VLT Unit Telescopes to the CCL. ESPRESSO will combine the efficiency of modern echelle spectrograph with extreme radial-velocity precision. It will achieve a gain of two magnitudes with respect to its predecessor HARPS, and the instrumental radial-velocity precision will be improved to reach cm/s level. Thanks to its ability of combining incoherently the light of the 4 UTs, ESPRESSO will offer new possibilities in various fields of astronomy. The Coudé Train is composed of a set of prisms, mirrors and lenses to deliver a pupil and an image in the CCL, including an Atmospheric Dispersion Compensator. The use of mainly refractive optics, and Total Internal Reflection, has the advantage of the inherent higher throughput, especially in the blue region of the spectrum. In this paper, we present the design of the Coudé Train, the evolution of the concept towards the manufacturing phase, its main characteristics and performances, and detail its subsystems: optical, mechanical and control electronics and software.

Ground-based and Airborne Instrumentation for Astronomy V
(Eds.) S. K. Ramsay, I. S. McLean, H. Takami

SPIE
Vol. 9147, Page 91478Q
2014

>> ADS>> DOI

Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

Proceed on CAUP's website|Go to IA website