.. index:: Nonlinearity, PTC, BFE (VIS); NISP LED flats .. _calobs-block-f-visNL-nispLED: **CALBLOCK-F-007:** VIS Nonlinearity, PTC, BFE and NISP LED flats ================================================================= .. include:: definitions.rst Observation configuration file ------------------------------ | :download:`ocf_CALBLOCK-F-007_VIS-LED1-ONSKYNL.csv ` | :download:`ocf_CALBLOCK-F-007_VIS-LED3-ONSKYNL.csv ` | :download:`ocf_CALBLOCK-F-007_VIS-LED4-ONSKYNL.csv ` | :download:`ocf_CALBLOCK-F-007_VIS-LED3-FLATNL.csv ` Scheduling ---------- Scheduled every 25-40 days, adding flexibility for survey planning. Cycle over 6 months between variants VIS-BFE-LED1-ONSKYNL, VIS-BFE-LED3-ONSKYNL, VIS-BFE-LED4-ONSKYNL, and VIS-BFE-LED3-FLATNL in the following pattern, such that the BFE LED cycling is twice per LED type per 6 months, and FlatNL occurs once every 6 months: | VIS-BFE-LED3-FLATNL | VIS-BFE-LED4-ONSKYNL | VIS-BFE-LED1-ONSKYNL | VIS-BFE-LED3-ONSKYNL | VIS-BFE-LED4-ONSKYNL | VIS-BFE-LED1-ONSKYNL | ..repeat.. Note: The initial introduction of the BFE-LED3 variant requires consecutive LED3 acquisitions, to catch up with the existing BFE-LED1 and -LED4 variants. Execute after F-001 if scheduled together back-to-back to avoid NISP persistence issues from NISP flats. In case of failure: Just skip and continue with the plan. The longer NISP component should be scheduled by EC-SURV. Time-critical ------------- No. Dependencies ------------ Must be executed after F-001 if scheduled back-to-back. Objective --------- **VIS:** Radiation damage may slightly alter voltages in the VIS electronics, changing the :ref:`VIS nonlinearity ` and hence the PSF model. The VIS nonlinearity must be monitored continuously. The on-sky variant of nonlinearity measurement requires a special dither pattern, set of exposure times, and certain stellar fields. Once every 6 months, we execute the flat variant of nonlinearity measurement, whose procedure is a replica of :ref:`REC-002 `. Additional FLAT pair acquisitions allow proper monitoring of :ref:`CTI `, :ref:`BFE ` and GAIN (obtained from the 1000 ADU :ref:`PTC `), via measurements of pixel covariance. To mitigate unwanted pixel covariance from intrinsic BIAS covariance, astronomical objects or sky, each FLAT pair should be taken at the same pointing. (Nominal ROS FLAT acquisitions are limited to once per pointing.) The excess covariance can then be estimated from Short Science pairs of 2 sec exposures at the same pointing (the open-shutter integration time of FLATs is 2 sec). **NISP:** Will take :ref:`LED flats `, needed on a monthly basis and providing additional data for :ref:`persistence ` monitoring. NISP is driving this calibration block (in terms of execution time). Apart from putting NISP into flat-field configuration at the beginning, the NISP observations do not require component movements and hence do not interfere with the VIS calibrations. Observations ------------ **VIS:** Aquisition consists of two parts: (1) VIS NL sequences and (2) FLAT/SS pairs, with BIAS interspersed approximately once every 6 hours. First, execute NL sequence on a stellar field. For the ONSKYNL variant, the VIS 4-exposure NL sequence is executed. This will take 4 consecutive open-shutter exposures with exposure times of 0 (flush- and readout-trail only), 25, 155 and 540s integration time. HGA repointing is required after each NL sequence. Repeat 16 times. A BIAS is acquired once every 8 NL sequences. Otherwise, execute the FLATNL variant with windowed FLATs, SS, and BIASs, identical to the procedure listed in the VIS-only ``CalBlock`` :ref:`REC-002 ` (also 16 pointings). The FLAT/SS pair acquisitions consists of a few additional pointings. Take 3x FLAT pairs of 1000 ADU fluence with LED3 for GAIN calibration, then take 6 FLATS (3x pairs) of 35000 ADU fluence for BFE (alternate between LED1, LED3, and LED4). Each FLAT-pair pointing must contain two SS exposures of EXPTIME=2 sec each. **NISP:** 30 LED flats for each LED, targeting 4 kADU fluence per exposure (90 e-/s LED flux). Afterwards, 4.5h of photo-MACC darks are taken for persistence decay and until VIS is done. .. code-block:: python :caption: **VIS on-sky nonlinearity sequence, BFE variant LED3 (VIS-BFE-LED3-ONSKYNL).** Slew to VIS NL field (Self-cal) NISP: Configure FWA = dark ------------------- VIS (NL, On-sky variant): Repeat 2x: take BIAS Repeat 8x: execute predefined VIS 4-exposure NL sequence Random dither in 3' box (HGA repointing + CDPU processing) take BIAS 3x Flats pairs at fluence 1000 ADU, with LED3 (GAIN) 2 Short Science (EXPTIME = 2 sec) Random dither in 3' box (HGA repointing + CDPU processing) 4 Flats at fluence: 35000 ADU, with LED3 (BFE-LED3 variant) 2 Short Science (EXPTIME = 2 sec) Random dither in 3' box (HGA repointing + CDPU processing) 2 Flats at fluence: 35000 ADU, with LED3 (BFE-LED3 variant) 2 Short Science (EXPTIME = 2 sec) Random dither in 3' box (HGA repointing + CDPU processing) ------------------- In parallel to VIS: No NISP wheel movements permitted at any time. for LED in [A, B, C, D, E]: LED flux = 90 e-/s Take 30 photo-MACC exposures Take 27 to 30 MACC(15,16,11) darks for persistence decay (VIS run must be longer). .. code-block:: python :caption: **VIS on-sky nonlinearity sequence, BFE variant LED1 (VIS-BFE-LED1-ONSKYNL).** Same as variant #1, but using LED1 instead of LED3 for BFE. [...] 4 Flats at fluence: 35000 ADU, with LED1 (BFE-LED1 variant) 2 Short Science (EXPTIME = 2 sec) Random dither in 3' box (HGA repointing + CDPU processing) 2 Flats at fluence: 35000 ADU, with LED1 (BFE-LED1 variant) 2 Short Science (EXPTIME = 2 sec) Random dither in 3' box (HGA repointing + CDPU processing) [...] .. code-block:: python :caption: **VIS on-sky nonlinearity sequence, variant LED4 (VIS-BFE-LED4-ONSKYNL).** Same as variant #1, but using LED4 instead of LED3 for BFE. [...] 4 Flats at fluence: 35000 ADU, with LED4 (BFE-LED4 variant) 2 Short Science (EXPTIME = 2 sec) Random dither in 3' box (HGA repointing + CDPU processing) 2 Flats at fluence: 35000 ADU, with LED4 (BFE-LED4 variant) 2 Short Science (EXPTIME = 2 sec) Random dither in 3' box (HGA repointing + CDPU processing) [...] .. code-block:: python :caption: **VIS Flat nonlinearity sequence, BFE variant LED3 (VIS-BFE-LED3-FLATNL).** Same as variant #1, but replace on-sky NL with Flat NL acquisition. [...] VIS (NL, Flat variant): BIAS settings: in full frame (at the top of the sequence) in windowed mode, VSTART=1086 (0x043E), VEND=2186 (0x088A) (the latter includes 120 overscan lines) Flat setting: LED3 with 3 mA Use windowed mode, VSTART=1086 (0x043E), VEND=2186 (0x088A) (the latter includes 120 overscan lines) EXPTIME should be 500ms up to 200ms LED_DELAY, otherwise add 500~2500s to LED_DELAY for EXPTIME SS setting: Use windowed mode, VSTART=1086 (0x043E), VEND=2186 (0x088A) (the latter includes 120 overscan lines) EXPTIME should match what is used in the FLAT (there should be two different EXPTIMEs per dither) Random dither in 3' box (HGA repointing + CDPU processing), 16x Full-frame BIAS in windowed mode: BIAS, SS, 2000, 1, 2, 3, 4, SS, dither in windowed mode: BIAS, SS, 2000, 5, 6, 7, 10, SS, dither in windowed mode: BIAS, SS, 2000, 20, 32, 40, 50, SS, dither in windowed mode: BIAS, SS, 2000, 100, 200, 300, 400, SS, dither in windowed mode: BIAS, SS, 2000, 500, 750, 1000, 1500, SS, dither in windowed mode: BIAS, SS, 2000, 3000, 3750, 5000, SS, dither in windowed mode: BIAS, SS, 2000, 6000, 6500, 7000, SS, dither in windowed mode: BIAS, SS, 2000, 8000, 2000, SS, BIAS, dither Full-frame BIAS in windowed mode: BIAS, SS, 2000, 1, 2, 3, 4, SS, dither in windowed mode: BIAS, SS, 2000, 5, 8, 9, 12, SS, dither in windowed mode: BIAS, SS, 2000, 16, 24, 28, 32, SS, dither in windowed mode: BIAS, SS, 2000, 64, 86, 128, 150, SS, dither in windowed mode: BIAS, SS, 2000, 400, 600, 750, 1000, SS, dither in windowed mode: BIAS, SS, 2000, 1250, 2500, 3500, SS, dither in windowed mode: BIAS, SS, 2000, 4000, 4500, 5500, SS, dither in windowed mode: BIAS, SS, 2000, 7500, 8500, 2000, SS, BIAS, dither take (full-frame) BIAS (GAIN) [...] .. csv-table:: **NISP LED flux lookup table. Use the settings for 90 e-/s.** :download:`CSV file ` :file: tables/NISP_LED_flux_LUT_flat.dat Fulfilling ---------- :ref:`calobs-vis-nonlinearity` :ref:`calobs-vis-ptc` :ref:`calobs-vis-bfe` (:ref:`calobs-vis-cti-eper`; optional) :ref:`calobs-nisp-led-flats` :ref:`calobs-nisp-badpixmap` (:ref:`calobs-nisp-persistence`; partially) (:ref:`calobs-nisp-inoculation`; optional) Targets and pointing constraints -------------------------------- :command:`Pointing`: No angle constraints .. csv-table:: SELFCAL-CENTER :download:`CSV file ` :widths: 15, 8, 8 :file: tables/targets-selfcal-center.dat Instrument configuration ------------------------ Instrument: Special. Methodology / Uplink procedure ------------------------------ :command:`Entity`: NISP, VIS :command:`Commanding Method`: :command:`Dither Sequence`: Random dither in 3' box Inter-operability constraints ----------------------------- NISP must not move any wheels during VIS operations. NISP must be configured before VIS starts taking data. In-orbit duration ----------------- :command:`In-orbit Duration`: 10.2 h (same for all variants) **VIS:** (8.2 h [NL] + 2.0 h [PTC & BFE] = 10.2 h) Duration of a single 4-exposure NL sequence without dither (repeated 16x): ``10s (1st exposure) + 2*297s (2nd-3rd exposures) + 545s (4th) + 4*72s (Readout) + 286s (4th processing) = 1723 s`` Duration of a single BIAS acquisition (repeated 3x): ``292 s`` Duration of PTC Flat/SS pairs: ``3037 s`` Duration of BFE Flat/SS pairs: ``2366 s (two BFE pairs) + 1462 s (one BFE pair)`` Duration per dither (repeated 18x): ``163 s`` (TBC) **NISP:** (10.0 h) Stabilisation time for each LED: 10s, DPU 10s after readout before new exposure starts, 111s for photo-MACC, 30 frames per LED. ``(10+111+10)s *30*5 = 5.5 h`` Additional 4.5 hours of persistence decay time: 10.0h Data volume ----------- Total: 50698 MB (ONSKYNL) or 53056 MB (FLATNL -- replace 64*VS with 31286 MB) VIS: ``64*VS + 3*VB + 6*400MB + (4*500MB + 2*600MB) + 6*850MB = 40378 MB`` NISP: ``150*NP + 30*NP = 10620 MB`` Processing input ---------------- :command:`Ground Processing Input Data`: TBD :command:`Data Description`: ONSKYNL variant: 64 VIS NL exposures, 3 VIS Bias, 6 low-fluence VIS SS, 6 low-fluence VIS flats, 6 high-fluence VIS flats, 150 NISP flats, 30 NISP darks. (FLATNL variant: Replace "64 VIS NL exposures" with 16 windowed VIS Bias, 16 windowed VIS SS, and 57 windowed VIS flats) Processing tools ---------------- TBD Quality control parameters -------------------------- DataModel: ``_ Contact person -------------- Calibration Lead Observation record ------------------ .. raw:: latex \clearpage .. raw:: latex \clearpage