W1J00 Transit Circle Catalog


Full Paper:

The W1J00 Transit Circle Catalog (W1J00)
Rafferty, T.J., Holdenried, E.R., and Urban, S.E.
Publ. USNO, 2nd series, vol. XXVII (part 1), Washington (2016)


Abstract:

We present the result of observations made with the Six-inch Transit Circle in Washington, D.C., between September 1977 and July 1982. The catalog, called W1J00, contains mean positions of 7267 stars, all but five are north of -30 degrees declination, and 4383 observations of solar system objects. Positions of stars are for mean epoch of observation, on equator and equinox J2000.0. Positions of solar system objects are apparent places. Error estimates are about 100 mas per coordinate for the majority of stars. 6-inch Transit Circle

Obtaining the Data:

The W1J00 data can be obtained via CDS (Strasbourg astronomical Data Center), catalog number I/334

Description:

The W1J00, named because it was the first (of two) Washington transit circle catalog to be referred to the Equinox of J2000.0, is the result of observations made with the Six-inch Transit Circle in Washington, D.C., between September 1977 and July 1982. The observing program was structured to be absolute, in the sense that the positions were not explicitly relying on any previous observations. The absolute positions were defined with respect to an internally consistent frame that was unique to the particular instrument. Following the reductions, comparisons with stars from the Hipparcos Catalogue (European Space Agency 1997) revealed unaccounted for systematic differences on the level of 100-200 mas. It was decided, therefore, to include data on both the absolute positions reduced in way common to many past Washington transit circle catalogs, as well as the positions differentially adjusted to the system of the Hipparcos Catalog.

The W1J00 contains mean positions of 7267 stars and 4383 observations of solar system objects. The majority of the stars fall into two categories; those from the Fifth Fundamental Catalog (FK5; Fricke et al 1988), and those from the Catalog Of 3539 Zodiacal Stars For The Equinox 1950.0 (Robertson 1940). The solar system objects include the Sun, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, eight minor planets (Eunomia, Flora, Hebe, Iris, Juno, Metis, Pallas, and Vesta), and the dwarf planet Ceres.

See also:
The 6-inch Warner and Swasey Transit Cicle home page.


Characteristics of the W1J00 catalog:

Category Range Average
Magnitudes -1.6 to 10.4 7.18
RA standard errors of the mean 15 to 460 mas 98 mas
Dec standard errors of the mean 10 to 400 mas 107 mas
RA Number of observations / star 3 to 187 10
Dec Number of observations / star 2 to 179 10
Declination coverage -39 to +90 degrees  


File Summary:

--------------------------------------------------------------------------------
 FileName      Lrecl  Records   Explanations
--------------------------------------------------------------------------------
ReadMe            80        .   This file
W1J00_stars.dat  113     7267   W1J00 star positions (means)
W1J00_solsys.dat  79     4383   W1J00 solar system object positions
--------------------------------------------------------------------------------


Byte-by-byte Description of file: W1J00_stars.dat

--------------------------------------------------------------------------------
   Bytes Format Units   Label    Explanations
--------------------------------------------------------------------------------
   1-  4  I4    ---     W1J00    W1J00 identifier
   6-  7  I2    h       RAh      Right Ascension ICRS, at Ep_RA (hours) (1)
   9- 10  I2    min     RAm      Right Ascension ICRS, at Ep_RA (minutes) (1)
  12- 17  F6.3  s       RAs      Right Ascension ICRS, at Ep_RA (seconds) (1)
  19- 21  I3    mas     e_RAs    Standard error of the mean, RA
  23- 25  I3    ---     NumRA    Number of observations used for RA
  27- 32  F6.3  yr      Ep_RA    Mean epoch of RA, minus 1900
  34- 39  F6.3  s       dRA      *RA (Absolute) - RA (ICRS) (2)
      41  A1    ---     DE-      Declination (ICRS) at Ep_DE (sign) (1)
  42- 43  I2    deg     DEd      Declination (ICRS) at Ep_DE (degrees) (1)
  45- 46  I2    arcmin  DEm      Declination (ICRS) at Ep_DE (minutes) (1)
  48- 52  F5.2  arcsec  DEs      Declination (ICRS) at Ep_DE (seconds) (1)
  54- 56  I3    mas     e_DEs    Standard error of the mean, DE
  58- 60  I3    ---     NumDE    Number of observations used for DE
  62- 67  F6.3  yr      Ep_DE    Mean epoch of DE, minus 1900
  69- 73  F5.2  arcsec  dDE      *DE (Absolute) - DE (ICRS)  (2)
  75- 80  F6.3  mag     Vmag     Visual magnitude (3)
  82- 87  I6    ---     HIC      Hipparcos Input Catalog number (4)
  88- 89  A2    ---     Comp     Hipparcos Input Catalog component (4)
  91- 98  I8    ---     DM       Durchmusterung number (4)
 100-103  I4    ---     FK5      FK5 number (4)
 105-113  A9    ---     WDS      Washington Double Star Catalog identifier (4)
--------------------------------------------------------------------------------
Note (1): Mean positions are on the International Celestial Reference
    System (ICRS), differentially reduced using the Hipparcos catalog.
    The epochs for the right ascension and declination coordinates are
    found in the Ep_RA and EP_DE fields respectively. 
Note (2): The observing program was designed to be an "absolute"
    catalog, independent of other catalogs.  Data reductions were
    carried out according to previous absolute transit circle
    catalogs.  Following the reductions, comparisons with the
    Hipparcos Catalogue revealed remaining, unaccounted for systematic
    deviations in the absolute positions.  The authors decided to
    differentially reduce the absolute positions using the Hipparcos
    data.  Those differential positions are listed in the RAh, RAm,
    RAs, DE-, DEd, DEm and DEs fields.  For users who may be
    interested in the absolute positions, values of the absolute
    position minus the differential position are provided in the dRA
    and dDE fields.
Note (3): Visual magnitude for identification purposes.  This was
    drawn from a variety of sources, but largely from the Hipparcos
    Input Catalogue.
Note (4): Cross references to several widely known catalogs are
    provided for convenience of the user.


Byte-by-byte Description of file: W1J00_solsys.dat

--------------------------------------------------------------------------------
Bytes  Format Units   Label   Explanations
--------------------------------------------------------------------------------
 1-  7  A7    ---     Obj     Solar system object identifier
 9- 10  I2    h       RAh     Right Ascen. (apparent) at Epoch (hours) (1, 2)
12- 13  I2    min     RAm     Right Ascen. (apparent) at Epoch (minutes) (1, 2)
15- 20  F6.3  s       RAs     Right Ascen. (apparent) at Epoch (seconds) (1, 2)
22- 27  F6.3  s       dRA     *RA (Absolute) - RA (HIP) (3)
    29  A1    ---     DE-     Declination (apparent) at Epoch (sign) (1, 2)
30- 31  I2    deg     DEd     Declination (apparent) at Epoch (degrees) (1, 2)
33- 34  I2    arcmin  DEm     Declination (apparent) at Epoch (minutes) (1, 2)
36- 40  F5.2  arcsec  DEs     Declination (apparent) at Epoch (seconds) (1, 2)
42- 46  F5.2  arcsec  dDE     *DE (Absolute) - DE (HIP)  (3)
48- 60  F13.5 day     Epoch   Julian date (UT1) of observation
62- 63  A2    ---     Obs     Observer code (4)
    65  A1    ---     Clamp   Clamp orientation of instrument (5)
    67  A1    ---     RALimb  Limbs or center of light measured in RA (6)
    69  A1    ---     DELimb  Limbs or center of light measured in DE (6)
--------------------------------------------------------------------------------
Note (1): Positions are apparent places, reduced to be systematically
    consistent with the Hipparcos Catalogue.  An apparent place is a
    geocentric direction of an object that takes into account orbital
    motion, space motion, light-time, light deflection, and annual
    aberration.  Apparent place is given with respect to the true
    equator and equinox "of date"; in this case, it is the date of
    observation found in the Epoch field. 
Note (2): In some cases, an observation is made in only right
    ascension or declination.  If only the right ascension coordinate
    was observed, then the declination seconds field (DEs) will be
    blank, as will dDE and DELimb.  If only the declination coordinate
    was observed, then the right ascension seconds field (RAs) will be
    blank, as will dRA and RALimb.
Note (3):  The observing program was designed to be an "absolute"
    catalog, independent of other catalogs.  Data reductions were
    carried out according to previous absolute transit circle
    catalogs.  Following the reductions, comparisons of stars with the
    Hipparcos Catalogue revealed remaining, unaccounted for systematic
    deviations in the absolute positions.  The authors decided to
    differentially reduce the absolute positions using the Hipparcos
    data.  Those differential positions are listed in the RAh, RAm,
    RAs, DE-, DEd, DEm and DEs fields.  For users who may be
    interested in the absolute positions, values of the absolute
    position minus the differential position are provided in the dRA
    and dDE fields.
Note (4): The Six-inch Transit Circle measurements were manual, in the
    sense that a person measured the position while looking through the
    instrument.  The observer code has the following meaning:
       RB = R.L. Branham
       TC = T.E. Corbin
       SD = S.J. Dick
       SG = F.S. Gauss
       EH = E.R. Holdenried
       EJ = E.S. Jackson
       BK = B.L. Klock
       RJ = R.J. Miller
       DR = M.D. Robinson
       RR = R.W. Rhynsburger
       TR = T.J. Rafferty
       CS = C.A. Smith
       RS = R.C. Stone
       ZY = Z.G. Yao
Note (5): The Six-inch was reversed (rotated 180 degrees in azimuth)
    interchanging the east and west pivots approximately every 30
    days. The orientation of the instrument was referenced to the
    location of the clamping device, which fixed the altitude of the
    instrument after it was pointed to a star, and thus referred to
    either as Clamp West or Clamp East.  The flag has the following
    meaning:
       W = Clamp West
       E = Clamp East
Note (6):  The Sun and planets subtend sizable disks in the
    instrument.  Primarily depending on the object, either the limbs
    or the center of light were observed. The flag has the following
    meaning:
       L = limb was measured
       C = center of light was measured 
       R = ring was measured (Saturn only)
       P = preceding limb was measured (Venus only)
       F = following limb was measured (Venus only)
       N = North limb was measured (Venus only)
       S = South limb was measured (Venus only)
    Despite how an object was observed, the W1J00 positions refer to
    the center of the object.

References:

    Fricke, W., Schwan, H., & Lederle, T., et al.  1988, Fifth
    Fundamental Catalogue (FK5), Part I. The Basic Fundamental Stars,
    Veroeff. Astron. Rechen-Institut Heidelb. No. 32  (Catalog I/149)

    Fricke, W., Schwan, H., Corbin, T., et al., 1991, Fifth
    Fundamental Catalogue FK5), Part II. The FK5 Extension, New
    Fundamental Stars, Veroeff. Astron. Rechen-Institut Heidelburg
    No. 33

    Perryman M.A.C., Lindegren L., Kovalevsky J., et al., 1997, "The
    Hipparcos Catalogue" (1997A&A...323L..49P)

    Robertson, J. 1940, Astron. Papers, Vol. X. part II, Washington
 
    Rafferty, T.J, Holdenried, E.R., and Urban, S.E., 2016, "W1J00
    Results of the Observations Made with the Six-inch Transit Circle
    1977-1982"