EOS P96 - 2.2.6.3 NIR Backgrounds

Doc:
Issue
Date
Page
VLT-MAN-ESO-14650-4942
P96
24.06.2015
44 of 161
ESO, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
2.2.6.3 NIR Backgrounds
The background of the new slits 0.6”JH and 0.9”JH with the blocking filter was compared to
the background of the normal slits 0.6” and 0.9”.
The table 11 below gives example of the background measurements at different wavelengths
for slits with and without filter.
Table 10: Background measurements of the slits with and without filter. The measurements
were normalized to a theoretical 1” slit. The RON is not included here.
Wavelength
nm
Background
with filter
e-/s/pix
Background
without filter
e-/s/pix
Reduction in
%
Reduction
factor
Sky darktime
e-/s/pix
1048
0.0195
0.056
65
2.9
0.018
1238
0.027
0.10
73
3.7
0.022
1300
0.035
0.13
73
3.7
0.040
1682
0.040
0.15
73
3.8
0.050
The measurements (see above table) show that with the blocking filter the background is
reduced in J and H bands by factors 3 to 4. They also show that at 1300nm, for the slits with
blocking filter the background would be sky limited (not taking into account the RON).
For more complete information, see next pages the figures and explanations.