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Proceedings Paper

High-resolution spectrograph of TNG: a status report
Author(s): Raffaele G. Gratton; Andrea Cavazza; Riccardo U. Claudi; Mauro Rebeschini; Giovanni Bonanno; Pietro Bruno; Antonio Cali; Salvatore Scuderi; Rosario Cosentino; Silvano Desidera
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Paper Abstract

The high resolution spectrograph of the TNG (SARG) was projected to cover a spectral range from (lambda) equals 0.37 up to 0.9 micrometer, with resolution ranging from R equals 19,000 up to R equals 144,000. The dispersing element of the spectrograph is an R4 echelle grating in Quasi-Littrow mode; the beam size is 100 mm giving an RS product of RS equals 46,000 at order center. Both single object and long slit (up to 30 arcsec) observing modes are possible: in the first case cross-dispersion is provided by means of a selection of four grisms; interference filters are used for the long slit mode. A dioptric camera images the cross dispersed spectra onto a mosaic of two 2048 X 4096 EEV CCDs (pixel size: 13.5 micrometer) allowing complete spectral coverage at all resolving power for (lambda) less than 0.8 micrometer. Confocal image slicers are foreseen for observations at R greater than or equal to 76,000; an absorbing cell for accurate radial velocities is also considered. SARG will be rigidly fixed to one of the arms of the TNG fork by means of an optical table and a special thermally insulating enclosure (temperature of all spectrograph components will be kept constant at a preset value by a distributed active thermal control system). All functions are motorized in order to allow very stable performances and full remote control. The architecture of SARG controls will be constructed around a VME crate linked to the TNG LAN and the instrument Workstation B by a fiber optic link.

Paper Details

Date Published: 9 July 1998
PDF: 8 pages
Proc. SPIE 3355, Optical Astronomical Instrumentation, (9 July 1998); doi: 10.1117/12.316762
Show Author Affiliations
Raffaele G. Gratton, Osservatorio Astronomico di Padova (Italy)
Andrea Cavazza, Osservatorio Astronomico di Padova (Italy)
Riccardo U. Claudi, Osservatorio Astronomico di Padova (Italy)
Mauro Rebeschini, Osservatorio Astronomico di Padova (Italy)
Giovanni Bonanno, Osservatorio Astrofisico di Catania (Italy)
Pietro Bruno, Osservatorio Astrofisico di Catania (Italy)
Antonio Cali, Osservatorio Astrofisico di Catania (Italy)
Salvatore Scuderi, Osservatorio Astrofisico di Catania (Italy)
Rosario Cosentino, Osservatorio Astrofisico di Catania (Italy)
Silvano Desidera, Univ. degli Studi di Padova (Italy)


Published in SPIE Proceedings Vol. 3355:
Optical Astronomical Instrumentation
Sandro D'Odorico, Editor(s)

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