VLT-MAN-ESO-14650-4942
P96
24.06.2015
62 of 161
ESO, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
2.4.11 VIS CCD pick-up noise
The pick-up noise in the VIS detector is present in every readout modes (with a deviation
from the background level of lower than 0.5%). This pick-up noise is comparable to the pick-
up noise measured on the UVES CCD for example. In case you want to observe faint targets
with long exposure times, it is not recommended to use the fast readout mode due to its
readout noise.
In addition the fast readout mode of the VIS CCD shows also very low level pattern with a
deviation from the background level of 1%.
Figures are available at:
http://www.eso.org/observing/dfo/quality/XSHOOTER/qc/problems/problems_xshooter.html
In the slow readout mode, the pick-up noise is lower and the patterns are not seen.
2.4.12 NIR –IFU parasitic reflections
In the IFU mode, some reflections of small irregularities of the edges of the IFU mirrors can
be visible in the images. However, they are faint and should not affect the observations.
An example is shown below in Figure 16 with an IFU flat field.
Figure 16: Example of small irregularities of the edges of the IFU mirrors in the NIR arm.
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