.. _calobs-nisp-spec-distortion: **CALPRODUCT-NS-003:** NISP-S Focal Plane Distortion ==================================================== .. include:: definitions.rst Parent requirement ------------------ | `R-CAL-B-NS-1120 `_ | `R-CAL-B-NS-1150 `_ Scheduling ---------- At least every 6 months, using secondary wavelengh calibrators (absorption line systems) in the SelfCal field. The full wavelengtj dispersion solution based on PN is done once during PV, and repeated once after 1 year in flight. Time-critical ------------- no Objective --------- Determine the Distortion Pattern across the NISP Spectro Focal Plane. This calibration is based on three mappings: 1. From sky (Gaia references) to 0th order using bright stars. 2. From 0th order to a reference wavelength in the 1st order. 3. Reconstruction of the wavelength dispersion solution (based on PN observations) Fulfilled by ------------ :ref:`calobs-block-pv-nisp-wavelength-dispersion` :ref:`calobs-block-pv-selfcal` :ref:`calobs-block-f-selfcal` Data volume ----------- No dedicated observations needed! Processing input ---------------- :command:`Ground Processing Input Data`: All calibration products to run the standard science pipeline (BPM, darks, flat, nonlinearity etc), astrometric reference catalog (Gaia), offline analysis :command:`Data Description`: No dedicated observations needed! Processing method ----------------- Distortion pattern is derived by comparing source positions against known (Gaia) astrometric positions (compared to 0th order centroids?), or by a self-cal approach utilizing the multiply dithered observations. Processing output ----------------- Distortion map of NISP-S focal plane, WCS solution for NISP spectro images, evaluation of impact of GWA position uncertainty Required accuracy, constraints ------------------------------ accurate source position measurements Processing tools ---------------- L1 science pipeline, source position measurements Quality control parameters -------------------------- DataModel: ``_ Contact person -------------- NISP-S calibration scientist Observation record ------------------ .. raw:: latex \clearpage .. raw:: latex \clearpage