Fundación Galileo Galilei - INAF Telescopio Nazionale Galileo 28°45'14.4N 17°53'20.6W 2387.2m A.S.L.

SARG - Slit Viewer

SARG slit viewer draw with the main components indicated SARG slit viewer integration with the TNG guide system

The Slit viewer is based on a scientific camera, equipped with one CCD EEV0520 (770 X 1152 frame transfer), a slit wheel with nine apertures and a movable turret. The wheel contains seven rejecting plates with the slits, an image slicers, one pinhole and one mirror. The movable turret contains an objective and an array of 22 X 22 lens for the Shack-Hartmann analysis. The light entering in the spectrograph goes to the slit. The plate on the inside of the slit viewer reflects part of this light in the slit viewer camera while the remaining light goes through the slit into the spectrograph. The physical sizes of the slits and the corresponding projected sizes in the sky are summarized in Tab.1. The slit viewer allows this features: the centering of the objects in the slit; the focusing of the telescope; the guide and the active optics correction.

CCD EEV 05-20

The main characteristics of the EEV 05-20 are listed in the following table as taken from the EEV data sheet

Pixel read out freq. 20-1500 kHz
Output amplifier sensitivity 2.0 µV/e-
Peak Signal 300 ke-/pixel
Dynamic Range 50,000:1
Spectral Range 420-1060 nm
R.O.N. 6 e- rms
Image area 770x1152 pixels
Image area 17.3X25.92 mm
Pixel Size 22.5 µ

The Quantum Efficency of the chip, as measured by is shown in the figure.

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