User Manual
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the drift in dispersion was somewhat higher (~0.2 px over 30 min; corresponding to a RV
drift of 200 m s
-1
) following metrology alignment than it was without metrology (0.05 px over
30 min; RV drift ~ 50 m s
-1
). Users should keep this in mind when planning to obtain RV
measurements with attached wavelength calibrations.
4.5 Throughput
The overall throughput of CRIRES has been measured on the spectrophotometric standard
Pi2Ori
by using the AO modes and the 0.4” slit width
.
The total throughput was derived by scaling the observed spectrum, expressed in e
-
/s/px
and corrected for silt loss, by the theoretical. Figure 28 shows the overall efficiency
measured on the observed spectrophotometric standard in four different settings (i.e.,
Y1029, J1228, H1559 and K2148). The throughput over the whole spectral range can be
downloaded from the ETC webpage. The observation of spectrophotometric standards is
part of the instrument monitoring plan, and as such the results shown in Figure 28 should
be regarded as preliminary.
Figure 28: Total observed throughput in 4 different settings. Preliminary results from
commissioning run in January 2021