I/246                  The ACT Reference Catalog                 (Urban+ 1997)
The ACT Reference Catalog
   Urban S.E., Corbin T.E., Wycoff G.L.
  <U.S. Naval Observatory, Washington D.C. (1997)>
ADC_Keywords: Positional data; Proper motions ; Astrographic zones;
              Historical catalog; Photographic catalog; Surveys;
              Cross identifications
Abstract:
    The U.S. Naval Observatory has completed the compilation of the ACT
    Reference Catalog, containing 988,758 stars covering the entire sky.
    The motivation behind the ACT was to provide accurate proper motions
    for the majority of the stars in the Tycho Catalogue (ESA SP-1200). To
    do this, positions from new reductions of the Astrographic Catalogue
    (AC 2000) were combined with those of Tycho. The large epoch span
    between the two catalogs yields proper motions about an order of
    magnitude more accurate than those published in the Tycho Catalogue.
    The astrometric data contained in the ACT Reference Catalog include
    positions, proper motions and error estimates. These are on the
    Hipparcos System (J2000.0) for epoch J2000.0. Photometric data (B and
    V) from Tycho are included. Additionally, cross references to the
    Tycho, AC 2000, Bonner Durchmusterung (BD), Cordoba Durchmusterung
    (CD), Cape Durchmusterung (CPD), Henry Draper (HD) and Hipparcos
    Catalogues are given.
File Summary:
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 FileName    Lrecl Records  Explanations
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ReadMe          80       .  This file
intro.tex      103     335  Introduction, latex version
intro.ps        72    1723  Introduction, postscript version
act0000.dat    159   15945  ACT Reference Catalog [00h 00m - 00h 30m[ (1)
act0030.dat    159   15221  ACT Reference Catalog [00h 30m - 01h 00m[ (1)
act0100.dat    159   14934  ACT Reference Catalog [01h 00m - 01h 30m[ (1)
act0130.dat    159   16128  ACT Reference Catalog [01h 30m - 02h 00m[ (1)
act0200.dat    159   15731  ACT Reference Catalog [02h 00m - 02h 30m[ (1)
act0230.dat    159   14975  ACT Reference Catalog [02h 30m - 03h 00m[ (1)
act0300.dat    159   14113  ACT Reference Catalog [03h 00m - 03h 30m[ (1)
act0330.dat    159   14199  ACT Reference Catalog [03h 30m - 04h 00m[ (1)
act0400.dat    159   14992  ACT Reference Catalog [04h 00m - 04h 30m[ (1)
act0430.dat    159   17025  ACT Reference Catalog [04h 30m - 04h 00m[ (1)
act0500.dat    159   21446  ACT Reference Catalog [05h 00m - 05h 30m[ (1)
act0530.dat    159   23249  ACT Reference Catalog [05h 30m - 06h 00m[ (1)
act0600.dat    159   25382  ACT Reference Catalog [06h 00m - 06h 30m[ (1)
act0630.dat    159   28837  ACT Reference Catalog [06h 30m - 07h 00m[ (1)
act0700.dat    159   31903  ACT Reference Catalog [07h 00m - 07h 30m[ (1)
act0730.dat    159   31099  ACT Reference Catalog [07h 30m - 08h 00m[ (1)
act0800.dat    159   29251  ACT Reference Catalog [08h 00m - 08h 30m[ (1)
act0830.dat    159   25605  ACT Reference Catalog [08h 30m - 09h 00m[ (1)
act0900.dat    159   21279  ACT Reference Catalog [09h 00m - 09h 30m[ (1)
act0930.dat    159   20678  ACT Reference Catalog [09h 30m - 10h 00m[ (1)
act1000.dat    159   19898  ACT Reference Catalog [10h 00m - 10h 30m[ (1)
act1030.dat    159   18206  ACT Reference Catalog [10h 30m - 11h 00m[ (1)
act1100.dat    159   17437  ACT Reference Catalog [11h 00m - 11h 30m[ (1)
act1130.dat    159   16921  ACT Reference Catalog [11h 30m - 12h 00m[ (1)
act1200.dat    159   16107  ACT Reference Catalog [12h 00m - 12h 30m[ (1)
act1230.dat    159   14847  ACT Reference Catalog [12h 30m - 13h 00m[ (1)
act1300.dat    159   15799  ACT Reference Catalog [13h 00m - 13h 30m[ (1)
act1330.dat    159   16783  ACT Reference Catalog [13h 30m - 14h 00m[ (1)
act1400.dat    159   16510  ACT Reference Catalog [14h 00m - 14h 30m[ (1)
act1430.dat    159   17229  ACT Reference Catalog [14h 30m - 15h 00m[ (1)
act1500.dat    159   18375  ACT Reference Catalog [15h 00m - 15h 30m[ (1)
act1530.dat    159   19450  ACT Reference Catalog [15h 30m - 16h 00m[ (1)
act1600.dat    159   20416  ACT Reference Catalog [16h 00m - 16h 30m[ (1)
act1630.dat    159   20817  ACT Reference Catalog [16h 30m - 17h 00m[ (1)
act1700.dat    159   22371  ACT Reference Catalog [17h 00m - 17h 30m[ (1)
act1730.dat    159   24219  ACT Reference Catalog [17h 30m - 18h 00m[ (1)
act1800.dat    159   26710  ACT Reference Catalog [18h 00m - 18h 30m[ (1)
act1830.dat    159   26741  ACT Reference Catalog [18h 30m - 19h 00m[ (1)
act1900.dat    159   27737  ACT Reference Catalog [19h 00m - 19h 30m[ (1)
act1930.dat    159   30156  ACT Reference Catalog [19h 30m - 20h 00m[ (1)
act2000.dat    159   30187  ACT Reference Catalog [20h 00m - 20h 30m[ (1)
act2030.dat    159   27188  ACT Reference Catalog [20h 30m - 21h 00m[ (1)
act2100.dat    159   22360  ACT Reference Catalog [21h 00m - 21h 30m[ (1)
act2130.dat    159   20619  ACT Reference Catalog [21h 30m - 22h 00m[ (1)
act2200.dat    159   19335  ACT Reference Catalog [22h 00m - 22h 30m[ (1)
act2230.dat    159   17887  ACT Reference Catalog [22h 30m - 23h 00m[ (1)
act2300.dat    159   16511  ACT Reference Catalog [23h 00m - 23h 30m[ (1)
act2330.dat    159   15950  ACT Reference Catalog [23h 30m - 24h 00m[ (1)
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Note (1): all these files should be concatenated to give the
    Full ACT catalog, originally split into 48 files, each 30min wide 
    in right ascension. The file names reflect the beginning of the right
    ascension band covered. For example, the file 'act0000.dat' starts at
    00 hours 00 minutes and contains all stars up to (but excluding) 00
    hours 30 minutes. The file 'act0530.dat' starts at 05 hours 30 minutes
    and contains all stars up to 06 hours 00 minutes.
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See also:
    I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
Byte-by-byte Description of file: act*.dat
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   Bytes Format Units      Label     Explanations
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   1-  2  I2    h          RAh       Right Ascension ICRS, Epoch=J2000.0 (hours)
   4-  5  I2    min        RAm       Right Ascension ICRS (minutes)
   7- 13  F7.4  s          RAs       Right Ascension ICRS (seconds)
      15  A1    ---        DE-       Declination ICRS, Epoch=J2000.0 (sign)
  16- 17  I2    deg        DEd       Declination ICRS, Epoch=J2000.0 (degrees)
  19- 20  I2    arcmin     DEm       Declination ICRS (minutes)
  22- 27  F6.3  arcsec     DEs       Declination ICRS (seconds)
  29- 35  F7.5  s/yr       pmRA      Proper Motion in RA, (sec of time/yr)
  37- 43  F7.4  arcsec/yr  pmDE      Proper Motion in Dec, arcsec/yr)
  45- 49  F5.1  mas        e_RAs     ?Stand. dev. of RA at Epoch 1991.25
                                      from Tycho (T14)
  51- 55  F5.1  mas        e_DEs     ?Stand. dev. of Dec at Epoch 1991.25
                                      from Tycho (T15)
  56- 61  F6.2  mas/yr     e_pmRA    ?Stand. dev. of Proper motion (RA),
  62- 67  F6.2  mas/yr     e_pmDE    ?Stand. dev. of Proper motion (DE),
  69- 74  F6.3  mag        BTmag     ?Blue magnitude from Tycho (T32)
  76- 81  F6.3  mag        VTmag     ?Visual magnitude from Tycho (T34)
  83- 88  F6.3  mag        B-V       ?Johnson B-V from Tycho (T37)
  90- 90  A1    ---        flag1    *[X] Astrometric Quality flag (T10)
  91- 91  A1    ---        flag2    *[1-8] Quality flag (T40)
  92- 92  A1    ---        flag3    *[GN]  Known variability flag (T47)
  93- 93  A1    ---        flag4    *[UVW] Variability from Tycho (T48)
  94- 94  A1    ---        flag5    *[YZ]  Duplicity from Tycho (T49)
  96-107  A12   ---        TYC       Tycho ID, embedded zeros for blanks
 109-115  I7    ---        AC2000    AC 2000 Number
 117-125  A9    ---        BD        BD identifier (T54)
 127-135  A9    ---        CD        CD identifier (T55)
 137-145  A9    ---        CPD       CPD identifier (T56)
 147-152  I6    ---        HD        ?Henry Draper Number (T53)
 154-159  I6    ---        HIP       ?Hipparcos Number (T31)
-------------------------------------------------------------------------------
Note on flag1:
   Astrometry Flag (T10 in Tycho):
   blank: a recommended astrometric reference star
   X: a dubious astrometric reference star in Tycho
Note on flag2:
   Quality flag (T40 in Tycho):
   1 through 5: very high to medium quality; probably single stars
   6:  perhaps non-single
   7:  low astrometric quality
   8:  perhaps non-stellar
   blank:  unassigned, observed by Hipparcos, not Tycho
Note on flag3:
   Known variability flag (T47 in Tycho)
   G:  Star in General Catalogue of Variable Stars, 4th Edition
   N:  Star in New Catalogue of Suspected Variable Stars
Note on flag4:
   Variability from Tycho (T48 in Tycho)
   U:  Apparent variability in Tycho data; may be due to duplicity
   V:  strong evidence of variability in the Tycho data
   W:  variability suspected in the Tycho data
Note on flag5:
   Duplicity from Tycho (T49 in Tycho)
   Y:  Investigation of duplicity made, no indication of duplicity
   Z:  No investigation of duplicity was performed
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References:
   The Hipparcos and Tycho Catalogues, 1997, European Space Agency, SP 1200
   New Reductions of the Astrographic Catalogue:  Plate Adjustments of the
      Algiers, Oxford I and II, and Vatican Zones, Urban, S.E, Martin, J.C.,
      Jackson, E.S., and Corbin, T.E., 1996A&AS..118..163U 1996A&AS..118..163U
   New Reductions of the Astrographic Catalogue:  Conventional Plate
      Adjustment of the Cape Zone, Urban S.E. and Corbin T.E.,
      1996A&A...305..989U 1996A&A...305..989U
   The U.S. Naval Observatory Astrographic Catalog Project, Urban, S.E.
      and Corbin, T.E.,  Galactic and Solar System Optical Astrometry,
      ed.  Morrison and Gilmore, Camb. Univ. Press, p. 11, 1994
(End)                  Sean E. Urban  [U.S. Naval Observatory]       04-Sep-1997