.. _NIRRelPhotoExpCalibration: [to complete] NIR Relative Photometric Calibration factors among exposures ============================================================== Metadata ______________________ +------------------------------------------------+----------------------------------------------------------------------------------------------+ | Data product name | DpdNirRelPhotoExpCalibration | +------------------------------------------------+----------------------------------------------------------------------------------------------+ | Data product custodian | NIR | +------------------------------------------------+----------------------------------------------------------------------------------------------+ | Name of the Schema file | .. raw:: html | | | | | | `euc-nir-RelPhotoExpCalibration.xsd `_ | +------------------------------------------------+----------------------------------------------------------------------------------------------+ | Processing Element(s) creating/using the data | The **DpdNirRelPhotoExpCalibration** is calculated for each Observation comparing photometry | | product | of sources extracted in | | | subsequent exposures. The task responsible of its creation is | | | **NIR_calculate_relative_exposures** task (under | | | *NIR_RelativePhotometry* project) inside the *NIR_ProcessField_Pipeline*. | | | | | | The catalog extracted from each exposure is compared with the ones of the others exposures. | | | The magnitude difference is calculated for each source in common between two exposures. Then | | | it is evaluated the median | | | values of those differences, after a sigma clipping to keep out variables and contaminant. | | | | | | At the end for each exposure is associated the median value among flux differences with all | | | the others exposures. | | | | | | In case of right photometric corrections (i.e. flats, detector offset factors) it is | | | expected to have a value close to 1 | | | for all exposures. Value that can move away from 1 in case of trouble in some specific | | | exposure photo calibration. | +------------------------------------------------+----------------------------------------------------------------------------------------------+ | Processing function using the data product | The **DpdNirRelPhotoExpCalibration** is applied by the **NIR_apply_relative_calibrations** | | | task (under | | | *NIR_RelativePhotometry* project) inside the *NIR_ProcessField_Pipeline*. | | | | | | We do not expect any variation in photometry among exposures due to the short time interval | | | among them. This value is | | | therefore considered as a quality parameter and not a photometric correction factor. | | | The task writes the keyword *QPRELEX*, and its corresponding error *QPRELEXE*, on the main | | | exposure header, that | | | traces a quality parameter, as described in :ref:`NIRCalibratedFrame` section. | +------------------------------------------------+----------------------------------------------------------------------------------------------+ Data Product structure description ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. DataProductDescrStart The main elements inside the *Data* section are: * **Filter**: The filter name (e.g. NIR_Y, NIR_J, NIR_H) * **ValidityRange**: Calibration file validity period estimated * **ObservationId**: Observation Id * **CorrectionFactorList**: a list of single exposure photometric offset * **Value**: detector photometric correction factor * **Error** (optional): detector photometric correction factor error * **Exposure**: exposure number .. DataProductDescrEnd .. DetailedDescEnd