From UCAC to URAT

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From UCAC to URAT

• Norbert Zacharias
• U.S. Naval Observatory
• Astrometry Department
• Cataloging Division
• nz_at_usno.navy.mil

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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 ...)

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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

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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.

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modify dome at CTIO
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observing at CTIO
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backend of astrograph
x-y slide
4k camera
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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)

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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

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StarScan plate measuring

• early epoch data for proper motions, bright stars
• CCD camera, step-stare mode
• accurate to lt 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

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StarScan plate measure machine Washington, DC
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SPM astrograph in Argentina
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KPNO 2.1 m

extragalactic reference frame link
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UCAC3 public release status

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

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U S N OR o b o t i cA s t r o m e t r i cT
e l e s c o p e

• 4-shooter camera
• plus
• new 0.85m telescope

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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'

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URAT optical design
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URAT cut side view

EOST, 2005
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URAT FASA2 (EOST 2005)
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0.9 m primary mirror delivered, Feb.08
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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

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U-mouse(if you can't get the rat,how about
a mouse?)
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10k camera dewar
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astrographwith 10k camera
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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

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STA1600B 4-shooter camera head concept front
view

• Cryostat window 350mm diameter, 300mm clear
  aperture.

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4-shooter camera dewar assemblyG.Luppino
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U-mouse project numbers

• 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 R17
• end of operation random error 2 mas at CTIO
• end of operation random error 3 mas at NOFS
• systematic errors lt 10 mas --gt ???

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• rebuilding astrograph in 24in dome

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astrograph new tube assembly
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USNO instrument shop Sep 2008astrograph tube
assembly
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fully funct. 10k chip image16outputsSTA2
008Sep 17
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summary

• UCAC3 all-sky to 16th mag, catalog in 2009
• URAT -gt 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 ?