Doc:
Issue
Date
Page
VLT-MAN-ESO-14650-4942
P96
24.06.2015
20 of 161
ESO, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
2.2.1.2 The Acquisition and Guiding slide
Light coming either directly from the telescope or from the Calibration Unit described above
reaches first the A&G slide. This structure allows putting into the beam either:
a flat 45˚ mirror with 3 positions mirror:
o
acquisition and imaging
: send the full 1.5’
1.5’ field of view to the A&G
camera. This is the position used during all acquisition sequences;
o
spectroscopic observations and monitoring
: a slot lets the central 10”
15” of
the field go through to the spectrographs while reflecting the peripheral field to
the A&G camera. This is the position used for all science observations.
o
artificial star
: a 0.5” pinhole used for optical alignment and engineering
purposes;
the IFU (described in Sect. 2.2.1.3);
a 50/50 pellicle beam splitter at 45˚ which is to used look down into the instrument
with the A&G camera and is exclusively used for engineering purposes.