.. index:: Persistence (NISP); Calibration observations .. _calobs-block-f-nisp-persistence: **CALBLOCK-F-018:** NISP Persistence ==================================== .. include:: definitions.rst Observation configuration file ------------------------------ | :download:`ocf_CALBLOCK-F-018.csv ` Scheduling ---------- In the monthly block between :ref:`calobs-block-f-selfcal` and :ref:`calobs-block-f-visNL-nispLED`. Like this it does not affect self-calibration, and any residual persistence from the NISP LED flats in F-007 does not bias the measurement of the persistence parameters. Also, the darks from subsequent F-007 provide sufficient persistence decay before survey operations resume. In case of failure, continue with the survey plan. Objective --------- We found considerable time variability of the persistence coefficients, and that the single PV calibration in :ref:`calobs-block-pv-nisp-persistence` is insufficient. Monthly observations are required to update the parameters for persistence correction. Observations ------------ There is a small dependence of the persistence parameters on the incident flux (on the order of a 10% change) as long as the detectors are not saturated. Thus we use a single LED fluence of 30 kADU (above the :ref:`baseline level `), followed by a series of short and long darks. LED 'E' is used for all persistence tests. We also take 3 trash darks at the beginning to allow for some persistence decay from the preceding on-sky observations. .. code-block:: python :caption: **Persistence calibration** Insert HGA repointings as necessary Take 3x MACC(4,16,4) trash darks Repeat 2x: Turn on LED 'E', fluence 30 kADU (690 e-/s) Take 1 flat field with MACC(4,16,4) Turn off LED Take 5 photo-MACC darks Take 4 spectro-MACC darks .. csv-table:: **NISP LED 'E' flux-lookup table for MACC(4,16,4)** :download:`CSV file ` :file: tables/NISP_LED-E_flux_LUT_persistence.dat Fulfilling ---------- :ref:`calobs-nisp-persistence` Targets and pointing constraints -------------------------------- :command:`Pointing`: off-sky observation. Straylight suppression as per MOCDA-SYS-003. Instrument configuration ------------------------ Instrument: NI-CU on, NI-CU off Methodology / Uplink procedure ------------------------------ :command:`Entity`: NISP :command:`Commanding Method`: NISP: Observation :command:`Dither Sequence`: None Inter-operability constraints ----------------------------- None In-orbit duration ----------------- :command:`In-orbit Duration`: 1.8 h ``3*111s + (111s+5*111s+4*565s)*2 = 1.8 h`` Data volume ----------- Total: 6129 MB ``15*NP + 8*NS = 2189 MB`` Processing input ---------------- :command:`Ground Processing Input Data`: Darks (without persistence) :command:`Data Description`: 2 flat fields, 10 photo-MACC darks, 8 spectro-MACC darks Required accuracy, constraints ------------------------------ Must be able to evaluate the persistence signal per pixel. Validation ---------- Update the time constants and amplitudes. Recovery -------- None. Just continue with the survey plan. Quality control parameters -------------------------- DataModel: ``_ Contact person -------------- NISP-P calibration scientist .. raw:: latex \clearpage