![]() |
|||||
---|---|---|---|---|---|
SPHERE IFS
Quality Control: detector calibration |
|||||
|
|
![]() |
The IFS-arm NIR detector is operated in cube mode (NDIT=NAXIS3) and nondestructive readmode (DET.READ.CURNAME=Nondest). All NDIT subintegrations are resolved as NDIT=NAXIS3 planes in a cube with 2048x2048 pixel (times NDIT planes). Detector characteristics are monitored via two raw types: DARK and BACKGROUND calibrations. Only BACKGROUND frames are used to calibrate science data. DARKs are acquired for monitoring the instrumental health.
IFS Dark frames are taken daily with the same setups as the IRDIS detector dark calibrations:
In addition dark frames are acquired with the DIT and NDIT of the science observations. The darks come as a single frames with one cube (NAXIS=3, NAXIS3=NDIT). QC1 parameters
Trending Dark level and the number of hot pixel is monitored for the three mentioned daily acquired health check setups. History
IFS background calibration frames are acquired with the DIT and NDIT of the dark frames. No prism is in the optical for background frames, however the background has a very small dependency on the CPI dichroic INS4.OPTI13.NAME=DIC_H or DIC_K. The pipeline does not (yet) subtract the dark of the same DIT. From the technical point of view the difference between an IFS dark frame and an IFS background frame is, that in dark the key INS.COMB.ICOR = N_NS_OPAQUE, which means that all three coronograhic elements are OPEN and the OCS1.INS.OPTI1.NAME = CLOSED, while in a background frame INS.COMB.ICOR = N_NS_CLEAR, which means that again all three coronopgraphic elements are OPEN and the INS.COMB.ICOR = OPEN as well. QC1 parameters
Trending The instrumental background depends on the dichroic in the common path interface (CPI).
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
![]() |
|