Astrometry

Electronic Data

Object databases

• SIMBAD (France) or Harvard
• NED

Digitized Sky Surveys

• Catalog name and institution
  • Source of the data
  • Digitizing device
  • Magnitude range
  • Number of objects
  • Sky coverage - What percentage of the entire sky is covered.
  • Epoch - When the observations were made
  • Equinox - Coordinate system
  • Bands - Wavelength of observations
  • Astrometric precision, resolution - Errors on position, proper motion and magnitude.
  • Purpose
  • Electronic access
  • Reference
• SAO (Smithsonian Astrophysical Observatory)
  • Source: A compilation from a large number of sources
  • Purpose: Satellite tracking (from the ground) and attitude-control on orbiting spacecraft
  • Date of compilation: 1960s
  • Number of objects: 260,000
  • Astrometric accuracy: 1".2 in the north, progressively worse south of -20 Dec, some errors up to 10" in the far-southern sky. (errors originate from the extrapolation of new positions using imprecise proper motions and epoch 1940 positions)
  • Sky coverage: Entire sky
  • Distribution: ADC Catalog 1131A. Available from the web or on ADC CD ROM Volume 4.
  • Equinox: J2000 (for latest version) USNO, ADC 1990
• AGK3
  • Number of objects: 200,000 (twice the density of SAO in northern hemisphere)
  • Sky coverage: north of -2 degrees of declination
  • Astrometric accuracy: 0.75 arcsec
  • Star data: position, proper motion, photo-blue magnitude
  • Magnitude range: complete to about blue magnitude 8.5, many stars down to mag. 12
  • Distribution: ADC catalog 1161B. Available from the web or on ADC CD ROM Volume 4.
  • Epoch: B1950.0
• ACRS (Astrographic Catalog Reference Stars) U. S. Naval Observatory
  • Source: A compilation from a large number of sources
  • Date of compilation: 1990
  • Astrometric Accuracy: Positions 0.3 arcsec, proper motions are factors of six to ten more accurate than SAO.
  • Sky coverage : Entire sky
  • Distribution: ADC Catalog 1171. Available from the web or on ADC CD ROM Volume 4.
  • Number of stars : 380,000
  • Reference: Corbin, 1991
• PPM (Positions and Proper Motions) Astronomisches Rechen-Institut in Heidelberg
  • Astrometric Accuracy: Positions 0.3 arcsec, proper motions are factors of six to ten more accurate than SAO. Blue magnitudes error can be as high as +-0.5, V magnitudes precision is 0.1 mag.
  • Number of stars : 470,000
• APM catalog, Royal Greenwich Observatory (RGO)
  • Source: POSS I glass copies
  • Digitizing device : APM, a laser based microdensitometer
  • Epoch: 1949 to 1958 (POSS I Survey) for northern sky. 1980 for southern sky ?
  • Magnitude range:
    • POSS (Northern sky) : Limiting magnitude 21.5 for the O plates and 20 for the E plates.
    • UKST (Southern sky): Limiting magnitude is 22.5 for the BJ plates and 21 for the R plates.
  • Internet access: Form based interface can retrieve a catalog of objects and a chart with stellar-like, unresolved objects are plotted as filled symbols, non-stellar objects are plotted as open symbols.
  • Number of objects : 150 million images recorded
  • Bands : Both blue O and red E plates.
  • Astrometric accuracy: Calibrated using 200+ PPM stars per plate. Resolution=1 arcsec. Sampling=1/2 arcsec
  • Sky coverage : Complete higher than +20 degrees from the galactic plane. Incomplete south of -20 degrees from galactic equator. Two regions : RA=2h DEC=15 and RA=23h DEC=10
• Revised APS Catalog of POSS I, University of Minnesota
  • Source: POSS I glass copies
  • Epoch: 1949 to 1958 (POSS I Survey)
  • Astrometric precision, resolution : rms of 0.2 arcsec.
  • Magnitude range: between magnitude 6 and ...
  • Internet access: Form based or SQL query based.
  • Problems: Zones of intense nebulosity have been excluded.
• GSC 1.2 , Guide Star Catalog (Space Telescope Science Institute and the Astronomisches Rechen-Institut)
  • Astrometric accuracy: 0.3 to 0.4 arcsec for stars fainter than 8th visal magnitude (five to ten times better than v1.1)
  • Number of Objects : 15,000,000
  • Purpose: provide a sufficient number of guide stars per field of view for the hubble space telescope star guidance system
• Hipparcos, European Space Agency (ESA)
  • Source: Hipparcos satellite
  • Number of objects: 118,218 stars
  • Astrometric accuracy: Positions accurate to 1 mas at epoch J1991.25, and proper motion to 1 mas/year. Magnitude accuracy : 0.1 mag.
  • Sky Coverage: Entire sky
  • Epoch : 1991.25
  • Equinox: J2000
  • Magnitude range:
  • Distribution:
    • Can be downloaded from the ADC Catalog number.
    • Celestia 2000 a CD ROM containing the compressed Tycho and Hipparcos catalogs with a window compatible data viewer and chart plotter. Can be purchased from the European Space Agency for a cost of U.S. $50.00
  • Online Java browser
  • Online Java browser with animation of proper motion
• Tycho, European Space Agency (ESA)
  • Source: Hipparcos star mapper
  • Number of objects: 1,058,332
  • Astrometric accuracy: Positions accurate to 25 mas at epoch J1991.25, and proper motion to 25 mas/year. Problem: It has been almost 8 years since the mean epoch, therefore position errors have degraded to 200 mas.
  • Sky Coverage: Entire sky
• AC 2000 : The Astrographic Catalogue on the System Defined by the Hipparcos Catalogue
  • Source: Positional catalog of data from the images measured and published as part of the Astrographic Catalogue (AC). The sky was divided among 20 observatories, by declination zones.
  • Number of objects: 4,621,836 stars
  • Sky Coverage: Entire sky
  • Epoch: average epoch of position is 1907
  • Magnitude range: All stars brighter than 11, many as faint as 13
  • Astrometric accuracy: Positions accurate between 150 and 300 mas at mean epoch of observation.
  • Coordinates: The positions are on the system defined by the Hipparcos Catalogue, having originally been reduced plate-by-plate using the Astrographic Catalog Reference Stars
  • Star data: magnitudes (on the Tycho B system) and cross referencing information
  • internet (14 files of approx. 8 MByte each). For CD ROM version contact Sean Urban ( seu@pyxis.usno.navy.mil ).
  • Size of the data: 435 MBytes (95 MBytes compressed)
  • References:
    • Urban,S.E., Corbin,T.E., Wycoff,G.L., Martin,J.C., Jackson,E.S., Zacharias,M.I., Hall,D.M. : 1998, Astron.J. 115, 1212. (Full article is online)
    • Urban,S.E., Corbin,T.E., Wycoff,G.L.: 1997, American Astronomical Society Meeting, 191, 1606
    • Urban,S, Corbin,T.: 1998, Sky and Telescope, volume 95, number 6, p.40.
    • Urban, S.E.: 1997, New Reductions of the Astrographic Catalogue, in Dynamics and Astrometry of Natural and Artificial Celestial Bodies, ed. Wytrzyszczak, Lieske and Feldman, Kluwer, p. 393.
    • Urban,S.E., Martin,J.C., Jackson,E.S.,and Corbin,T.E. : 1996, New Reductions of the Astrographic Catalogue: Plate Adjustments of the Algiers, Oxford 1, Oxford 2, and Vatican zones, Astron. & Astrophys. Supp. Ser. 118, 163
    • Urban, S.E. and Corbin, T.E.,1996, New Reductions of the Astrographic Catalogue: Conventional Plate Adjustment of of the Cape Zone, Astron. & Astrophys., 305, 989.
    • Urban, S.E. and Corbin, T.E., 1994, The U.S. Naval Observatory Astrographic Catalog Project, in Galactic and Solar System Optical Astrometry, ed. Morrison and Gilmore, Camb. Univ. Press, p. 11.
    • Eichhorn, Heinrich. 1974, Astronomy of Star Positions. New York: Fredrick Ungar Publishing Co., 1974 pp. 279-323
    • Turner, H.H., 1912, The Great Star Map, London: John Murray Publishers, 1912
• The ACT Reference catalog (ACT = AC 2000 and Tycho)
  • Source: Positions from new reductions of the Astrographic Catalogue (AC 2000) were combined with those of the Tycho Catalog. Tycho stars not matched at this time were re-examined using no application of proper motion. A further search for known high proper motion stars was made. Special consideration was given to multiple star systems.
  • Number of objects: 988,758 stars
  • Sky Coverage: Entire sky
  • Purpose: Provide accurate proper motions for the majority of the stars in the Tycho Catalogue (ESA SP-1200)
  • Astrometry accuracy: Proper motion accurate to 2.4 mas/year. About 80 percent of stars are better than 3.5 mas/year. Starting with the Tycho data the positional accuracies will remain under 100 mas for almost 30 years. The large epoch span between the AC 2000 and Tycho catalogs yields proper motions about an order of magnitude more accurate than those found in the Tycho Catalog (which are 25 mas/year)
  • Distribution: Can be downloaded from USNO or from the ADC as Catalog 1246 (about 50 MBytes compressed)
  • Internet Access:
  • Star data: J2000 Hipparcos System positions. Proper motion and error. B, V from Tycho catalog. Cross references from Tycho, AC 2000, Bonner Durchmusterung (BD), Cordoba Durchmusterung (CD), Cape Durchmusterung (CpD), Henry Draper (HD) and Hipparcos Catalog
  • References:
    • The ACT Reference Catalog Sean E. Urban, Thomas E. Corbin and Gary L. Wycoff: Astron. J., 115, 2161
    • Urban,S, Corbin,T., Wycoff, G. : 1997, American Astronomical Society Meeting, 191, 5707.
    • Urban,S, Corbin,T.: 1998, Sky and Telescope, volume 95, number 6, p.40.
    • Corbin,T.E., Urban,S.E.: 1988, IAU Symposium 133 Mapping the Sky, ed. S. Debarbat, J.A. Eddy, H. K. Eichhorn and A. R. Upgren, Kluwer, Dortrecht, p. 287
    • Corbin,T.E., Urban,S.E.: 1990, IAU Symposium 141 Inertial Coordinate System on the Sky, ed. J. Lieske and V.K. Abalakin, Kluwer, Dortrecht p. 433.
    • Eichhorn,H.: 1974, Astronomy of Star Positions, Fredrick Ungar, p. 283
    • Urban, S.E.: 1993, The U.S. Naval Observatory's Astrographic Catalogue Project, in Workshop on Databases for Galactic Structure, ed. A.G.D Philip, B. Hauck, and A.R. Upgren, L. Davis Press p. 145
    • Urban, S.E., 1997, New Reductions of the Astrographic Catalogue, in Proceedings of IAU Colloquium 165, ed. Wytrzyszczak, I.M., Lieske, J.H., and Feldman,R.A, Kluwer Academic Publishers, p. 493
    • Urban, S.E., Corbin, T.E., Wycoff, G.L., Martin, J.C., Jackson E.S., Zacharias, M.I., and Hall D.M., 1997, The AC 2000: The Astrographic Catalogue on the Hipparcos System, in preparation.
    • Urban, S.E., Corbin, T.E., and Wycoff, G.L., 1998, The ACT Reference Catalog, in press
  • Problems: Only two positions are used to determine proper motion. Flaws in either catalog or unmodeled binary star orbits may lead to spurious proper motions.
• The Twin Astrographic Catalog (TAC) Version 1.0
  • Source: AC 2000 and U.S. Naval Observatory Twin Astrograph (blue, yellow lens)
  • Number of Objects: 705,679 (3 times more stars than PPM or ACRS. Higher star density than the Tycho catalog)
  • Sky coverage: -18 to 90 degrees declination
  • Epoch: 1977-1986
  • Astrometric accuracy: Position errors are 90 mas per coordinate at epoch of observation. TAC is 3 times more precise than the PPM or ACRS in the northern hemisphere at current epochs. Provides independent, high precision positions for a large fraction of the Tycho stars at an epoch about 10 years earlier than the Tycho mean epoch.
  • Magnitude range: to B=12
  • Reference
    • Turon,C. et al. 1992, The Hipparcos Input Catalogue, European Space Agency (ESA) SP-1136, Volume 1-7, ESTEC, Noordwijk
    • Urban,S.E., Corbin,T.E. 1996, New reductions of the Astrographic Catalogue, A&A 305, 989
    • Worley,C.E. and Douglass,G.G., Washington Double Star Catalog, 1996.0,
    • Zacharias,N., Zacharias,M.I., Douglass,G.G., Wycoff,G.L. : 1996, AJ 112, 2336
• USNO-A1.0 : A Catalog of Astrometric Standards, Monet, D. et al.
  • Source of the data: Original POSS-I glass plates ! Blue/red overlaps of the detection lists generated from scans of POSS-I O and E plates (>= -30 degrees) and SRC-J and ESO-R plates (<= -35 degrees).
  • Digitizing device: Precision Measuring Machine (PMM) The 2D scanner was built and operated by the U. S. Naval Observatory Flagstaff Station
  • Number of object: 488,006,860
  • Magnitude range: 11 to 20th (O=21, E=20, 20th magnitude in the north and J=22, and F=21 or 21th in the south The limiting magnitude is brighter for objects with extreme colors, and follows from the requirement for a detection on both the blue and red survey plate. Stars brighter than 11th magnitude are included from the Guide Star Catalog.
  • Distribution: Institutions can request the survey from the USNO, no charge
  • Internet Access:
    • ESO/ST-ECF USNO-A1.0 Catalog Server provided by European Southern Observatory (ESO) and the Space Telescope - European Coordinating Facility (ST-ECF).
    • Lowell Observatory (maximum number of selectable objects limited to 5000)
  • Purpose: provide a grid of astrometric reference objects over the whole sky (used for asteroid discovery and orbit determination)
  • Sky coverage: Entire sky. From -30 to +90 declination POSS I stars appearing on both red (I band) and blue plates (E-band) and from -90 to -35 declination stars appearing on both SRC-J and ESO-R plates
  • Color Bands: Northern part (POSS-I) O and E emulsions filters, Southern part (SRC) IIIa-J and IIIa-F emulsions.
  • Epoch: Blue plate coordinates are used.
  • Format: 10 CDs
  • Star data: Includes Red and blue magnitudes.
  • Coordinates: J 2000 stored as 32 bit BIG_ENDIAN binary integer (RA in decimal hours)*15*3600*100, and ((DEC in decimal degrees)+90)*3600*100 same format as Hipparcos/Tycho
  • Astrometric precision, resolution: Coordinates have 0.25 arcseconds accuracy and photometric error is 0.25 magnitudes. however a number of users have reported large (~1 or 2 mags) zero point errors for various Southern plates. Original PMM scan errors are 0.15 arcsec and 0.15 magnitude. The southern photometry may be recomputed when recalibrating the survey to the Hipparcos and Tycho reference frame. Astrometric calibration based on the Space Telescope Science Institute's Guide Star Catalog version 1.1. (will soon be replaced with a calibration to the European Space Agency's Hipparcos and Tycho catalogs)
  • Problems: There are holes in the catalog in the vicinity of bright stars, regions of nebulosity, crowded fields, etc.
  • References:
    • Monet,D., Bird,A., Canzian,B., Harris,H., Reid,N., Rhodes,A., Sell,S., Ables,H., Dahn,C., Guetter,H., Henden,A., Leggett,S., Levison,H., Luginbuhl,C., Martini,J., Monet,A., Pier,J., Riepe,B., Stone,R., Vrba,F., Walker,R.: 1996, USNO-SA1.0, (U.S. Naval Observatory, Washington DC).
• USNO-SA 1.0 (Subset of A1.0)
  • Number of sources: 54,787,624 Purpose: Provide an astrometric reference catalog for asteroid hunters and other folks who do not need the entire USNO-A catalog. Subset of USNO-A1.0 which could fit on one CD with spatially uniform sample of solar type stars.
  • Magnitude range: 16 to 19th white stars (about a quarter of the stars are outside of this range)
  • Color Bands: Solar like spectrum, most are 0.5 < (m_B-m_R) < 2.0 or approximately white
  • Distribution: Institutions can request the survey from the USNO, no charge
  • Format: one CD.
  • Problems: In crowded regions the brightest stars are chosen. Strong selection effect biased towards the purpose of finding quide stars.
• Technical page from The Amateur Sky Survey
• RealSky (Epoch 1955)
  Northern POSS-I
  • Source: 100 times compressed DSS survey
  • Epoch: 1955
  • Magnitude: 19th
  • Resolution: 1.7 arcsec
  • Band: red
  • Sky coverage: -15 to +90 declination
  Southern SERC-J
  • Epoch: 1978
  • Magnitude: ?
  • Band: blue
  • Sky coverage: -90 to 0
• Digitized Sky Survey
  • Source: 10 times compressed data from scan of the Northern POSS-I red and southern SERC-J blue plates.
  • Epoch: 1955 (Northern) and 1980 (Southern)
  • Astrometric accuracy: 1.7 or 1.0 arcsec per pixel
  • Storage: Whole sky on 102 CDROMS. Each image is 6.5 x 6.5 degrees occupying :
    • 0.4 GBytes for 1.7 pixel scans (about 14000 x 14000 pixels per plate)
    • 1.1 GBytes for 1.0 pixel scans (about 23040 x 23040 pixels per plate)
  • Electronic access : STScI, FITS or GIF, up to one degree fields of view can be requested. Enter the J2000 coordinates to obtain image centered at those coordinates. You can enter an object's name and obtain their coordinates from SIMBAD or NED. Portions of the second generation survey are going online (POSS-II) and can also be requested from this site.
• Sloan Digital Sky Survey
  • Epoch: 1998,
  • Coverage : galactic latitude > 30 degrees,
  • Magnitude range: 23rd magnitude,
  • Bands: 5 color bands,
  • Precision:
  • Purpose: To survey 100,000 QSOs and mapping Galaxy distibution

Faint star catalogs

• Stellar catalogs used in reducing The Amateur Sky Survey (TASS) observations (ses also new Catalogs)
• ADC Catalogs
• ADC 7207 : Quasars and Active Galactic Nuclei (8th Ed.) (Veron+ 1998)
  • Number of objects: 11,358 Quasars
  • References:
    • Veron-Cetty,M.P., Veron, P.: 1998, ESO Sci. Rep., 18, 1

Journals

• The Astrophysical Journal & Supplement   European Site
• The Astronomical Journal   European Site
• Astronomy & Astrophysics
• Astronomy & Astrophysics Supplement Series
• Publications of the Astronomical Society of the Pacific  European Site
• Information Bulletin on Variable Stars

Software

• DAOPHOT (executable from University of Ljubljana, Slovenia)
• DoPhot (executables from tass)
• FITSView v1.30 (executables from tass
• Naval Observatory Vector Astrometry Subroutines (NOVAS)
• WCSTools 2.3.2 : Convert pixel coordinates to RA and Declination
• Janes,K.A., Heasley,J.N.: 1993, PASP 105, 527 Stellar Photometry Software (SPS) source code is available
• PSF modelling photometry software:
  • CAPELLA Llebaria,A., Perichaud,L., Leporati,L., Debray,B.: 1989, ESO Conf and Workshop Proc. 31, 85. 1st ESO/ST-ECF Data Analysis Workshop, ed Grosbol,P.J., Murtagh,F., Harris,R.H.>,
  • DAOPHOT Stetson,P.B.: 1987, PASP 99, 191
  • DoPHOT Mateo,M., Schecter,P.L.: 1989, ESO Conf and Workshop Proc. 31, 69. 1st ESO/ST-ECF Data Analysis Workshop, ed Grosbol,P.J., Murtagh,F., Harris,R.H.
  • HAOPHOT Gilliland,R.L.: 1990, ASP Conf. Ser. 8, CCDs in Astronomy, ed. Jacoby,G.H. (San Francisco, ASP), p. 281
  • INVENTORY Kruszewski,A.: 1989, ESO Conf and Workshop Proc. 31, 29. 1st ESO/ST-ECF Data Analysis Workshop, ed Grosbol,P.J., Murtagh,F., Harris,R.H.
  • ROMAFOT
    • Buonanno,R., Buscema,G., Corsi,G., Ferraro,C.E., Ianniscola,G.: 1983, A&A 126, 278
    • Buananno.R., Ianniscola,G.: 1989, PASP 101, 294
  • STARMAN Penny,A.J., Dickens,R.J.: 1986, MNRAS 220, 845
• Fukushima,T.: 1996, AJ 112, 2858. A Fast Procedure Solving Kepler's Equation for Elliptic Case.
  • Java implementation of the code
• Fukushima,T.: 1997, AJ 113, 1920. A Procedure Solving the Extended Kepler's Equation for the Hyperbolic Case.
• Animation of a binary star system. (Java applet)

Other sites

• Hipparcos: Double and Multiple Stars
• Second epoch POSS-II and SES surveys
• USNO Astrometry dept.
  • IAU Commision 24 on photographic astrometry
• Double Star Library at CHARA
• Worley,C.E., Heintz, W.D.: 1983, Fouth Catalog of Orbits of Visual Binary Stars (get data or from ADC)
• Astrometrica
• John Rogers : Computer Aided Astrometry
• Observing Asteroids
• Guide Star Catalog
• USNO A 1.0
• Minor Planet Center
• Lowell Observatory
• Hunting Asteroids
• Orbital elements and GIF images of the orbits of 150 visual binaries
• Widest visual binaries sorted by decreasing separation
• Binary Star Systems
• Dan Bruton's Eclipsing Binary Stars page
• Double Star Obsever Edited/published by Ronald C. Tanguay
• Double Stars To Follow by Martin Gaskell
• Astrometry & Dynamics: Double & Multiple Stars Royal Observatory of Belgium (Brussels)
• Two body celestial dynamics (from course by Dr. T.J. Sumner 1997/8)
• Mizar from APOD Binary stars
• White dwarfs

Article of Interest

• Luyten,W.J.: 1979, NLTT Catalogue (Minneapolis: Univ. Minnesota)
• Luyten,W.J., & Hughes, H.S. : 1980, Proper Motion Survey with the 48 Inch Schmidt Telescope: LV. First Supplement to the NLTT Catalogue (Minneapolis: Univ. Minnesota)
• Proceedings from the Hipparcos Venice '97 symposium
  • Lindegren,L.: 1997, The Hipparcos Catalogue Double and Multiple Systems Annex
  • Halbwachs,J.-L. et al.: 1997, Statistical Study of the Visual Double Stars in the Tycho Catalogue
  • Söderhjelm, S. et al. : 1997, Binary Star Masses from Hipparcos
• Robichon,N. et al.: 1995, Astronomy & Astrophysics, 304, 132. Reduction of Schmidt plates
• Martin,C., Mignard,F. : 1998 A&A, 330, 585. Mass determination of astrometric binaries with Hipparcos. II. Selection of candidates and results
• Acker,A., Fresneau,A., Pottasch,S.R., Jasniewicz,G. : 1998,A & A 337, 253. A sample of planetary nebulae observed by HIPPARCOS. Conlusion: Ground based distances are overestimated.
• Croswell,K.: 1982, Astronomy, December. "Contact Binaries: Stars That Touch".
• Croswell,K.: 1985, Astronomy, May, "When Stars Coalesce".
• Trimble,V.: 1984., Sky and Telescope, October. "A Field Guide to Close Binary Stars".
• Meeus,J.: 1971, Sky and Telescope, January, "Some bright visual binary stars I" p.21
• Meeus,J.: 1971, Sky and Telescope, February, "Some bright visual binary stars II" p.88
• Gossman,D.: 1989, Sky and Telescope, October, "Ligh Curves and their Secrets" p.410 (Basic program GOSS.BAS is available from Sky Publishing web site)
• Gravitational lenses

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