.. index:: Photometric large-scale flat (NISP) .. _calobs-nisp-phot-large-scale-flats: **CALPRODUCT-NP-003:** NISP-P Large-Scale Flat ============================================== .. include:: definitions.rst Parent requirement ------------------ | `R-CAL-B-NP-1200 `_ Scheduling ---------- Monthly Time-critical ------------- No Dependencies ------------ None Objective --------- Reconstruct matching broad-band large-scale flats for the YJH filters from the :ref:`calobs-block-f-selfcal` observations. Fulfilled by ------------ :ref:`calobs-block-pv-selfcal` :ref:`calobs-block-f-selfcal` Data volume ----------- TBD Processing input ---------------- :command:`Ground Processing Input Data`: BPM :command:`Data Description`: Processing method ----------------- By comparing stellar fluxes from a set of widely dithered images, a large-scale illumination correction is calculated. This calibration removes simultaneously the large-scale non-uniformity present in the NI-CU beam (:ref:`calobs-nisp-led-flats`) as well as any vignetting effects from the telescope and instrument optics (NI-CU illuminates the focal plane array directly, without passing through any optics). Processing output ----------------- Large-scale flats for the YJH filters. Trend analysis Required accuracy, constraints ------------------------------ TBD Processing tools ---------------- L1 small scale flat pipeline, trending statistics, offline analysis for trapping/de-trapping, persistence Quality control parameters -------------------------- DataModel: ``_ Contact person -------------- NISP-P calibration scientist .. raw:: latex \clearpage