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VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010

VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010. Wide field plates observations of stars from Earth Orientation Catalogs (EOC). Yavor Chapanov 1 , Katya Tsvetkova 2 , Milcho Tsvetkov 2 , Jan Vondrák 3 , Cyril Ron 3 , Vojtéch Štefka 3.

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VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010

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  1. VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010 Wide field plates observations of stars from Earth Orientation Catalogs (EOC) Yavor Chapanov1, Katya Tsvetkova2, Milcho Tsvetkov2, Jan Vondrák3, Cyril Ron3, Vojtéch Štefka3 1 – Central Laboratory for Geodesy, Bulgarian Academy of Sciences 2 – Astronomical Institute, Bulgarian Academy of Sciences 3 – Astronomical Institute, Academy of Sciences of Czech Republic

  2. VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010 DATA SOURCE EARTH ORIENTATION CATALOGUE EOC-4 - 4418 objects, determined from 4.5 million observations of latitude/universal time WIDE-FIELD PLATE DATABASE WFPDB - Catalogues of Wide-Field Plates with more than 600000entries

  3. VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010 EARTH ORIENTATION CATALOGUE EOC-4

  4. VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010 EARTH ORIENTATION CATALOGUE EOC-4 DECLINATION EPOCHS - significant number of stars with mean epochs before 1990 - long observational series

  5. VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010 EARTH ORIENTATION CATALOGUE EOC-4 RA EPOCHS - small number of stars with mean epochs between 1975 and 1990 - short observational series

  6. VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010 EARTH ORIENTATION CATALOGUE EOC-4 Proper motion in declination - stars with pmDE>0.05”/a are potential source of systematics

  7. VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010 EARTH ORIENTATION CATALOGUE EOC-4 Proper motion in RA - stars with pmRA>0.05”/a are potential source of systematics

  8. VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010 EARTH ORIENTATION CATALOGUE EOC-4 Parallax - non-linear proper motion is more visible for stars with greater parallax

  9. VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010 EARTH ORIENTATION CATALOGUE EOC-4 STAR MAGNITUDE - between 0 and 12 mean magnitude 6.5 - significant number of brightstars star images cover more pixels - better accuracy

  10. VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010 WFPDB – Telescopes and plates VIEW ANGLE [degree] - 1, 3, 5, 7, 20, … APERTURE [cm] - 10, 12, 14, 16, 34, 40, 60, 67, … PLATE SCALE ["/mm] - 830, 295, 860, 258, 300, 102, 115, 96, … SCAN RESOLUTION [dpi] - 300, 600, 1200, 2400, 4800, 9600, …

  11. VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010 WFPDB – Star position accuracy • ACCORDING PLATE SCALE (emulsion corn 10m) • 100"/mm - ±0.5" • 60"/mm - ±0.3" • 13"/mm - ±0.06"(Rozhen) • ACCORDINGSCAN RESOLUTION • 300dpi=12d/mm+scale 13”/mm - ±0.5" • 600dpi=24d/mm+scale 13”/mm - ±0.3" • 1200dpi=47d/mm+scale60"/mm - ±0.6" • 2400dpi=94d/mm+scale100"/mm - ±0.5" • 4800dpi=189d/mm+scale100"/mm –(±0.3“) • 9600dpi=378d/mm+scale100"/mm –(±0.1“)

  12. VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010 WFPDB – Plates: position accuracy PLATE CENTER - current accuracy (1”,1”), necessary (0.1”, 0.1”), determined by 7-parameter transformation PLATE ORIENTATION - determined by 7-parameter transformation ANGULAR DISTANCE FROM THE CENTER - max 5°

  13. VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010 WFPDB – Plates: Access FREE ACCESS - compressed images SCAN RESOLUTION - as high, as possible (interpolation) SEARCH - by the scale parameter (<100”/mm) TOOLS - 7-parameter transformation(plate center) - distortion model improving - star identification and coordinates extraction

  14. VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010 CONCLUSIONS • The WFPDB provide significant number of plates, containing a given star. The observation epochs cover century time span, which is useful to improve star catalogs. • It is necessary to improve the free access to the digitized plates and to add some new options in the search engine and tools: • - improve resolution to 4800dpi or more and compress the images • - search for plates with scale <100arcsec/mm • - online tool for identification of a group of stars from a given plate sequence • - accurate determination of the plate centers and their orientation by 7-parameter transformation

  15. VII BSAC  "ASTROINFORMATICS" – Chepelare, 1-4 June 2010 THANK YOU FOR ATTENTION

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