EOS P96 - d) Efficiency of observations without ADCs at different given slit angles and airmasses

Doc:
Issue
Date
Page
VLT-MAN-ESO-14650-4942
P96
24.06.2015
29 of 161
ESO, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
Nodding mode, AM=1.35
Ratios no ADCs/with ADCs
Arm, slit angle
Average
range
std
UVB parallactic
0.87
0.87-0.9
0.01
UVB perpendicular
0.82
0.56-1.0
0.15
VIS parallactic
0.88
0.82-0.9
0.02
VIS perpendicular
0.81
0.66-0.99
0.11
The measurements were performed on short integration times and if possible in stable
conditions of the seeing.
d) Efficiency of observations without ADCs at different given slit angles
and airmasses
In this subsection a summary is presented first, a modeling for narrower slits is shown in
second, and finally the detailed measurements corresponding to the first part are provided.
We consider here the ratios of the observation at 45 degrees or 90 degrees of the parallactic
angle to the parallactic angle for different airmasses.
Summary:
Arm
airmass
Ratio 45/parall
Ratio 90/parall
UVB
1.10
0.98
0.83
UVB
1.51
0.84
0.63
UVB
2.20
0.31
0.18
VIS
1.10
0.87
0.80
VIS
1.51
0.92
0.72
VIS
2.20
0.63
0.31
The similar information was computed theoretically and is shown in the following plots.
On those plots for observations at 90 degrees of the parallactic angle, slits of 0.4” in the UVB
arm (top), 0.5” in the VIS arm (bottom) and a seeing of 0.8” have been considered.