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Photometric Calibration Jorge F. García Yus GEMINI Observatory Barolo 2001
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GSC-II Photometric Calibration Calibrators: GSPC-I B, V magnitudes and brighter than 15 th TYCHO B Tycho, V Tycho magnitudes and brighter than 11.5 th GSPC-II B, V, R magnitudes and fainter as 20 th Color transformations: One pair for each pass band available Range of validate
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Cont…. Photographic plate material and filters: IIIaJ+GG385, IIIaF+RG610, IIIaJ+GG395, IIIaF+OG590…… Scanning and digitalization: GAMMA 1 and GAMMA 2, laser and white light Pipeline data processing: SKYPROCESSOR INVENTORY DEBLENDER FINDCAT PHOTOSOL APPLY_CALYB
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GSC 2 Photometric Calibration: from GSH files
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Number of calibrators per field
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Statistic are over estimated by known problems. Stars with more than one color, calibrators with poor astrometry and multiple observations.
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Inconsistence in early reference catalogs version.
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UKST southern hemisphere material: IIIaJ+GG395 (blue) and IIIaF+OG590 (red)
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POSS-II northern hemisphere material: IIIaJ+GG385 (blue) and IIIaF+RG610 (red)
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POSS-II special constrains: location of original photometric calibrators are vignetted
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GSC 2.2.01 data: photometric analyze From 1715 square degrees (full sky coverage) Rejected 77 southern fields where J magnitude are not present (+/- 10° galactic latitude, SMC and LMC) ~5% Founded and rejected 32, plates with suspicious photometry. (mainly large color residuals) Total for analyze 1606 plates or 1606 square degrees
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FaintArt.#s#caldiserrPlateDateComment 19.519.638050.70.10XJ0057-JAN-2000 18.718.748550.60.11XP00523-NOV-1999 19.819.715780.10.11XJ00719-DEC-2000 19.118.714060.10.13XP0077-JAN-2000 17.216.915150.20.11XJ0167-JAN-2000No faint GSPC2 16.215.915410.20.13XP0167-JAN-2000No faint GSPC2 17.116.814130.10.09XJ01720-DEC-1999No faint GSPC2 17.717.522930.10.13XP01714-OCT-1999No faint GSPC2 19.819.814040.30.10XJ0207-JAN-2000 18.518.414240.30.13XP0207-JAN-2000 20.820.736990.20.17XJ05720-DEC-1999 18.618.738060.10.13XP05717-JAN-2000 20.220.116980.20.15XJ0746-SEP-2000 10.911.31860.00.14XP0741-NOV-1999No GSPC2 20.620.716270.00.11XJ21919-DEC-2000 19.819.913560.10.11XP21918-JUL-2001 21.021.239582.50.15XJ28828-OCT-1999 17.417.22770.30.18XP28827-DEC-2000No faint GSPC2 19.219.367750.10.12XJ3408-MAR-2000 low galactic latitude 17.617.5011740.00.19XP34021-JUN-2000No faint GSPC2 20.320.512801.20.18XJ4286-JAN-2000 19.719.715041.00.14XP4286-DEC-1999 20.420.246750.10.10XJ49323-AUG-2000 19.219.326100.00.11XP49320-OCT-1999 20.820.823240.20.10XJ5337-JAN-2000 18.718.722720.30.13XP5337-DEC-1999 20.320.411660.40.11XJ59911-JAN-2000 18.418.311770.40.12XP59916-JAN-2001 18.418.121340.20.08XJ6531-FEB-2000 17.417.221500.20.12XP65316-DEC-1999No faint GSPC2 20.020.011950.40.12XJ6606-JAN-2000 11.611.801320.00.16XP66016-DEC-1999No GSPC2 20.720.622461.30.16XJ6697-JAN-2000 19.018.812011.90.12XP6692-DEC-2000 20.220.1520210.40.12XJ70118-DEC-2000bad matching? 17.917.717620.70.08XP70128-OCT-1999 19.419.2111810.10.10XJ7735-OCT-2000bad matching? 18.418.422090.60.13XP77324-JAN-2000
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FaintArt.#s#caldiserrPlateDateComment 20.620.714020.20.16XJ8477-FEB-2000 20.220.113280.30.15XP84722-NOV-1999 20.921.01970.50.10XJ88014-JAN-2001 19.819.81710.00.15XP88011-NOV-1999 19.919.822720.30.13XS01612-JAN-2000 20.820.415790.00.13S01630-JAN-2001 19.819.614320.10.15XS16210-DEC-1999 21.021.1110030.10.16S16221-DEC-2000bad matching? 20.119.912600.20.12XS19210-DEC-1999 20.820.424920.00.19S19220-SEP-2000 19.619.5214850.10.14XS3726-FEB-2001bad matching? 18.117.811370.00.17S3728-SEP-1999 21.120.992060.10.15S43015-NOV-1999No red plate 20.620.519140.10.17S4525-OCT-2000No red plate 16.916.731550.30.13XS46811-DEC-1999No faint GSPC2 17.917.334730.10.11S46821-SEP-2000No faint GSPC2 17.417.666790.00.27S5221-DEC-1999* large error 20.120.119810.10.16ER6332-FEB-2001bad matching? 20.921.216030.10.11S63329-NOV-2000 18.117.821940.40.19ER7036-FEB-2001 18.818.918230.20.12S70328-NOV-2000bad matching? 20.320.5214170.10.15ER77412-FEB-2001bad matching? 21.021.128180.20.13S7744-JAN-2001bad matching?
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Star completeness for 1606 pair of plates
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All object completeness for 1606 pair of plates
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J - F color
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GSC 2 color distribution as a galactic latitude function
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Conclusions GSC 2.2.01 provide at least 1 calibrated star (photometrical (J,F) and astrometrical) in a 2.5x2.5 minute squares. Dense enough for the telescope operation The number of fields that need photometric recalibration are less than 5% The major effort for the next release will be improving the accuracy for the faint end, providing an even product with a very good data quality for astrophysical research An effort still needs is in the pass band characterization, specially oriented for the final users (Observing tools, proposals planning, etc.) …….may be my homework…
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