EOS P96 - 5.Instrument and telescope overheads; 5.1.1 Summary of telescope and instrument overheads

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VLT-MAN-ESO-14650-4942
P96
24.06.2015
100 of 161
ESO, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
5. Instrument and telescope overheads
5.1.1 Summary of telescope and instrument overheads
Table 14: overheads
Acquisition and setup
Telescope pointing, guide star acquisition,
start active optics. X-shooter backbone
flexure measurement.
360s
Interactive acquisition loop
See a
Instrument setup at the end of acquisition
SLIT: see b
IFU: see b
Delay of start of exposures, see c
Observations
Detector readout,
See also d
UVB
1x1, slow / fast: 68s / 16s
1x2, slow / fast: 34s /8s
2x2, slow / fast: 17s / 4s
VIS
1x1, slow / fast: 89s / 21s
1x2, slow / fast: 45s / 11s
2x2, slow / fast: 22s / 5s
NIR
1.46
Each telescope offset
15 s
Acquisition and guiding camera readout
Less than 1s
The overheads will be modified if some imaging is introduced in the OB, after commissioning
all the values will be published. However from the preliminary tests; the readout of the AG
camera is fast (less than 1s), the change of filter takes less than 20s and the instrument
setup depends from which mode the instrument goes to the imaging mode. In case of IFU it
takes about 45s. In slit mode it takes lass than 10s.
a) Acquisition overheads
the acquisition time depends on the integration time set in the AG camera:
Direct acquisition loop = Preset time
+ (Tel offset + AG_EXPOSURE)*3
+ AG_EXPOSURE (saved)
Blind offset acquisition loop = Preset time
+ (Tel offset+ AG_EXPOSURE)*3
+ telescope blind offset to target
+ AG_EXPOSURE for check
+ AG_EXPOSURE saved.
Tel offset= The telescope offset could be up to 15 sec
The telescope (blind) offset to the target could be up to 30 sec.
Acquisition template | acquisition time (s)
-----------------------+--------------------
XSHOOTER_slt_acq =360+(Tel offset + AG_EXPOSURE)*3+AG_EXPOSURE
XSHOOTER_ifu_acq 360+(Tel offset + AG_EXPOSURE)*3+AG_EXPOSURE