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From UCAC to URAT

Norbert Zacharias U.S. Naval Observatory Astrometry Department Cataloging Division nz@usno.navy.mil. From UCAC to URAT. acknowledgement. UCAC (CCD setup, survey): T.Rafferty, M. Germain, J.Pohlman, ... all observers & site support (O.Saa, D.Castillo ... T.Tilleman)

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From UCAC to URAT

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  1. Norbert Zacharias U.S. Naval Observatory Astrometry Department Cataloging Division nz@usno.navy.mil From UCAC to URAT

  2. acknowledgement • UCAC (CCD setup, survey): • T.Rafferty, M. Germain, J.Pohlman, ... • all observers & site support (O.Saa, D.Castillo ... T.Tilleman) • M.Zacharias, C.Finch, G.Wycoff, .... • UCAC (proper motions): • S.Urban, W. van Altena, T.Girard, A.Klemola, D.Monet, ... • U-mouse (detector): • STA (R.Bredthauer, ...), G.Luppino ... • U-mouse (astrograph): • USNO instrument shop (G.Wieder, ...) • USNO management (R.Gaume, K.Johnston ...)

  3. U S N OC C DA s t r o g r a p hC a t a l o g “red lens” astrograph + 4k CCD combined with early epoch photographic data

  4. UCAC observing • 1997 – 2004 (all-sky completed) • 579 – 642 nm bandpass • R = 8 to 16 mag • positions accurate to 20 mas (10 – 14 mag) • incl. proper motions (various early catalogs) • thanks Bill ! SPM = major contributor • most accurate astrometry for fainter than Hip.

  5. modify dome at CTIO

  6. observing at CTIO

  7. backend of astrograph x-y slide 4k camera

  8. UCAC products • UCAC1 (2000) : part of Southern Hemisphere • UCAC2 (2003) : -90 to +50 deg decl. • UCAC3 (2009) : • all-sky coverage; re-processing all pixel data • much improved completeness (bright stars, doubles) • improved astrometry (empirical profile fits, global iterations) • improved proper motions bright: new data: AGK2 • improved proper motions faint: re-reduct. NPM, SPM • improved photometry (1 band)

  9. re-processing pixel data • 4.5 TB compressed • dark, flat handling • double star fits • empirical profiles • identify overexposed • multi-level results, flags • keep “fit crash”

  10. StarScan plate measuring • early epoch data for proper motions, bright stars • CCD camera, step-stare mode • accurate to <= 0.5 micrometer absolute • Zacharias et al. 2008, PASP • 1930 AGK2: 1,900 plates • 1976..1995 ZA: 2,300 plates • 1983..1990 BB: 900 plates

  11. StarScan plate measure machine Washington, DC

  12. SPM astrograph in Argentina

  13. KPNO 2.1 m extragalactic reference frame link

  14. UCAC3 public release status • reductions completed: • pixel re-processing --> x,y data, various models • “plate adjustment”, systematic errors (model, FDP, CTE) • StarScan data up to RA, Dec; SPM: final model decisions • levelsof products, options for release: • mean position catalog (80 million stars, all sky) include only if >= 2 detections + PM available • extract and identify minor planets -> separate catalog • identify double stars -> flags in main catalog • individual epoch RA, Dec of all detections • pixel data images (very noisy, dark current ...)

  15. US N ORo b o t i cAs t r o m e t r i cTe l e s c o p e 4-shooter camera plus new 0.85m telescope

  16. URAT overview • USNO Robotic Astrometric Telescope • 0.85 m aperture, focal length = 3.6 m • 4.5 degree diameter field of view • large format detector (world largest CCD) • 2 px / FWHM at 1.0 arcsec seeing • 9 micrometer pixel size • 4 CCDs, each 95 mm on a side • 60 s / 240 s integration • 13 to 21 mag • goal 5 mas for 'well exposed stars'

  17. URAT optical design

  18. URAT cut side view EOST, 2005

  19. URAT FASA2 (EOST 2005)

  20. 0.9 m primary mirror delivered, Feb.08

  21. status of URAT project • telescope: • optical design studies completed • primary mirror: delivered Feb. 2008 • no funding to complete new telescope • detector: • 10.5k by 10.5k CCD chip produced successfully • thinning of 2 science grade chips May/July 2007 • 10k camera complete, 1st light October 2007 • 4-shooter camera funded, delivery March 2009

  22. “U-mouse”(if you can't get the “rat”,how about a “mouse”?)

  23. 10k camera dewar

  24. astrographwith 10k camera

  25. URAT phase 1 = U-mouse • currently no funding for new telescope • take 4-shooter camera, put at astrograph • complete re-make of astrograph 2007/08 • move to CTIO or NOFS, begin new survey 2009 • 28 sq. deg. per exposure! • 11 mas per image coord. (well exposed star) • multiple sky overlaps per year, 7 - 18 mag • clocked anti-blooming: seems to work! • solve for positions, motions + parallax

  26. STA1600B 4-shooter camera head concept – front view • Cryostat window – 350mm diameter, 300mm clear aperture.

  27. 4-shooter camera dewar assemblyG.Luppino

  28. sky area per hemisphere 25,000 sq.deg field size per exposure 25 sq.deg number of fields 1000 2 exposures / field / epoch 60, 240 sec time for 1 field (exp.pair) 6 min time for 1-fold sky overlap 100 hour avail. observ. time / year 2,200 hour (CTIO) ...dark time, good seeing 1,500 hour (CTIO) numb. sky overlaps in 2 years 30 at CTIO numb. sky overlaps in 2 years 15 at NOFS single measure precision 11 mas(cent.+atm) ...for well exposed stars R= 11..15; 40 mas R=17 end of operation random error 2 mas at CTIO end of operation random error 3 mas at NOFS systematic errors < 10 mas --> ??? U-mouse project numbers

  29. rebuilding astrograph in 24in dome

  30. astrograph new tube assembly

  31. USNO instrument shop Sep 2008astrograph tube assembly

  32. fully funct. 10k chip image16outputsSTA2008Sep 17

  33. summary • UCAC3: all-sky to 16th mag, catalog in 2009 • URAT -> Umouse: first light 2009 • 111 million pixel CCD detector on sky tested in 2007 • use re-furbished astrograph for phase 1, 2008 • get 4-shooter camera by March 2009 • observe 2-3 years per site (NOFS, CTIO) • catalog of positions, proper motions, parallaxes 2012 ?

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