The Global Pool The Global Pool AstroWise Workshop AstroWise Workshop list of active and potential calibrators

The Global Pool Why –Calibration refinement What –Astrometric calibration –Photometric calibration How –DB storage –Global processing Why –Calibration refinement What –Astrometric calibration –Photometric calibration How –DB storage –Global processing

Why a global pool Higher precision –Astrometric reference frame Large errors on dense catalogs Small errors on sparse catalogs –Photometric calibration grid New calibrators –Increase density of astrometric grid –Build secondary photometric standards Higher precision –Astrometric reference frame Large errors on dense catalogs Small errors on sparse catalogs –Photometric calibration grid New calibrators –Increase density of astrometric grid –Build secondary photometric standards

What is the global pool Data store of (potential) calibrators Source Pool –Ever growing –Source extractions Positions Fluxes Catalog –Predefined slice from the Source Pool Calibrators –Catalog with calibration status sources Data store of (potential) calibrators Source Pool –Ever growing –Source extractions Positions Fluxes Catalog –Predefined slice from the Source Pool Calibrators –Catalog with calibration status sources

Actions on global pool Use –Astrom – input reference catalog –Photom – input standard star catalog Add –SAssociate single chip/global catalogs Validate –Check reliability of information Modify –Derive new values Use –Astrom – input reference catalog –Photom – input standard star catalog Add –SAssociate single chip/global catalogs Validate –Check reliability of information Modify –Derive new values

How to build the global pool Filled with known calibrators –USNO, GSC, Hipparcos,...(weights) –Landolt, SDSS, etc. Adding potential candidates –Selections from the standard pipeline processing –One or more characteristics Position measurements Flux measurements Evaluating candidates Deriving new calibrators Filled with known calibrators –USNO, GSC, Hipparcos,...(weights) –Landolt, SDSS, etc. Adding potential candidates –Selections from the standard pipeline processing –One or more characteristics Position measurements Flux measurements Evaluating candidates Deriving new calibrators

Filling the global pool (1) At calibration pipeline processing –Astrometric pipeline Calibration source extractions Overlap source extractions Other high SNR extractions (stellar objects) –Multiple extraction of same source Re-run of pipeline Reobservation of sky area Associations of ‘same’ source (association lists) At calibration pipeline processing –Astrometric pipeline Calibration source extractions Overlap source extractions Other high SNR extractions (stellar objects) –Multiple extraction of same source Re-run of pipeline Reobservation of sky area Associations of ‘same’ source (association lists)

Filling the global pool (2) PipelineAssociate calibratorextraction PipelineAssociate extractionextraction Pool Source IngestAssociate calibratorcandidate Physical source

Filling the global pool (3) Identityunique id per physical source Originexternal, measured, derived Positionmeasured or derived positions Positional error Signalsignal/flux/magnitude Signal error Astrom weight0 … 1 Photom weight0 … 1 Qualityunknown, calibrated Version1 … N Variabley/n Proper motiony/n Statusunknown, validated, calibrator FlagsTBD ObsdateChipidfiltid

Filling the global pool (4) Calibrator –Reference calibrator Original calibration data Multiple source extractions –New calibrator Derived calibration data Multiple source extractions Potential calibrator –No calibration data –Multiple source extractions Calibrator –Reference calibrator Original calibration data Multiple source extractions –New calibrator Derived calibration data Multiple source extractions Potential calibrator –No calibration data –Multiple source extractions

Deriving calibrators (1) Evaluate a given source (verify()) –Determine candidate status Stable (proper motion, variable,...) High SNR information Enough measurements Promote/demote to/from calibrator –Model description of instrument –Large time interval processing Evaluate a given source (verify()) –Determine candidate status Stable (proper motion, variable,...) High SNR information Enough measurements Promote/demote to/from calibrator –Model description of instrument –Large time interval processing

Deriving calibrators (2) Model description Astrometric –Optical path modelling –Independent parametrization from standard pipeline processing –History on extracted source information –Association information –Multiple pointings –Multiple filters Model description Astrometric –Optical path modelling –Independent parametrization from standard pipeline processing –History on extracted source information –Association information –Multiple pointings –Multiple filters

Deriving calibrators (3) Create new entry in Source Pool –New derived information –Status: calibator –Quality: calibrated –Weight: 0 … 1 (errors) Demote older calibrator entry –Last = best? –History of calibration Create new entry in Source Pool –New derived information –Status: calibator –Quality: calibrated –Weight: 0 … 1 (errors) Demote older calibrator entry –Last = best? –History of calibration

Deriving calibrators (4) Id:1 seqnr:1 Status:calibrator Obsdate: Id:1 seqnr:2 Status:unknown Obsdate: Id:1 seqnr:3 Status unknown Obsdate: Id:1 seqnr:4 Status:unknown Obsdate: Id:1 seqnr:5 Status unknown Obsdate: Id:1 seqnr:6 Status:calibrator Obsdate: Id:1 seqnr:7 Status: unknown Obsdate: Id:1 seqnr:8 Status: unknown Obsdate: Id:2 seqnr:1 Status:calibrator Obsdate: Id:2 seqnr:2 Status:unknown Obsdate: Id:2 seqnr:3 Status unknown Obsdate: Id:2 seqnr:4 Status:unknown Obsdate: Id:2 seqnr:5 Status unknown Obsdate: Id:2 seqnr:6 Status:unknown Obsdate: Id:2 seqnr:7 Status: calibrator Obsdate: Id:2 seqnr:8 Status: unknown Obsdate: Id:3 seqnr:1 Status: unknown Obsdate: Id:3 seqnr:2 Status: unknown Obsdate: Id:3 seqnr:3 Status: calibrator Obsdate:

Calibration consquences Every N months a new calibrator set –Regenerate all calibrated data –Regenerate all extractions that added to the Source Pool Iterative process Calibration refinement throughout observing Every N months a new calibrator set –Regenerate all calibrated data –Regenerate all extractions that added to the Source Pool Iterative process Calibration refinement throughout observing

Global Pool Virtual sky of calibrators