1. The Global Pool The Global Pool AstroWise Workshop 20-11-2006 AstroWise Workshop 20-11-2006 list of active and potential calibrators

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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)

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

9. 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

10. 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

11. 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

12. 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

13. 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

14. Deriving calibrators (4) Id:1 seqnr:1 Status:calibrator Obsdate: 20030405 Id:1 seqnr:2 Status:unknown Obsdate: 20051201 Id:1 seqnr:3 Status unknown Obsdate: 20051204 Id:1 seqnr:4 Status:unknown Obsdate: 20060101 Id:1 seqnr:5 Status unknown Obsdate: 20060523 Id:1 seqnr:6 Status:calibrator Obsdate: 20060723 Id:1 seqnr:7 Status: unknown Obsdate: 20061010 Id:1 seqnr:8 Status: unknown Obsdate: 20061011 Id:2 seqnr:1 Status:calibrator Obsdate: 20030405 Id:2 seqnr:2 Status:unknown Obsdate: 20040909 Id:2 seqnr:3 Status unknown Obsdate: 20041001 Id:2 seqnr:4 Status:unknown Obsdate: 20041230 Id:2 seqnr:5 Status unknown Obsdate: 20050305 Id:2 seqnr:6 Status:unknown Obsdate: 20050809 Id:2 seqnr:7 Status: calibrator Obsdate: 20060723 Id:2 seqnr:8 Status: unknown Obsdate: 20061120 Id:3 seqnr:1 Status: unknown Obsdate: 20060402 Id:3 seqnr:2 Status: unknown Obsdate: 20060505 Id:3 seqnr:3 Status: calibrator Obsdate: 20060723

15. 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

16. Global Pool Virtual sky of calibrators