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I/250               The Tycho Reference Catalogue       (Hog+ 1998)

The Tycho Reference Catalogue Hog E., Kuzmin A., Bastian U., Fabricius C., Kuimov K., Lindegren L., Makarov V.V., Roeser S. <Astron. Astrophys. 335, L65 (1998)> =1998A&A...335L..65H
ADC_Keywords: Positional data; Proper motions ; Astrographic zones; Historical catalog; Photographic catalog; Surveys; Cross identifications Mission_Name: Hipparcos Keywords: astrometry - reference catalogues - proper motions - Astrographic Catalogue - Tycho Catalogue Abstract: The Tycho Reference Catalogue (TRC) contains high-quality positions and proper motions for 990182 stars of the Tycho Catalogue. The proper motions were derived from Tycho positions and Astrographic Catalogue positions reduced to the Hipparcos system. The median accuracy of the TRC position components is 40 mas at J1991.25. The median accuracy of the proper motion is about 2.5 mas/yr. Systematic errors are less than about 1.0 mas(/yr). The quality of the proper motions in TRC is assessed by comparison with the Hipparcos and Tycho Catalogues. Comparison with the recent ACT Catalogue which is based on an independent reduction of the same observations as used for constructing the TRC is reported. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file catalog.dat 148 990182 The TRC catalogue index.dat 6 9538 Index to TRC
See also: I/220 : The HST Guide Star Catalog (Lasker+ 1992) I/239 : The Hipparcos and Tycho Catalogues (ESA 1997) I/246 : The ACT Reference Catalog (Urban+ 1997) Byte-by-byte Description of file: catalog.dat
Bytes Format Units Label Explanations
1- 4 I4 --- TYCID1 [1,9537]+= TYCID1 from TYC (1) 6- 10 I5 --- TYCID2 [1,12119] TYCID2 from TYC (1) 12 I1 --- TYCID3 [1,2] TYCID3 from TYC (1) 14- 25 F12.8 deg RAdeg Right Ascension, ICRS, at epoch J2000 27- 38 F12.8 deg DEdeg Declination, ICRS, at epoch J2000 40- 45 F6.1 mas/a pmRA [-212.7,210.1] prop. mot. in RA * cos(dec) 47- 52 F6.1 mas/a pmDE [-216.6,210.6] proper motion in Dec 54- 60 F7.2 a epRA [1923.68,1991.25] mean epoch of RA (2) 62- 68 F7.2 a epDE [1934.88,1991.25] mean epoch of Dec (2) 70- 74 F5.1 mas e_RAdeg s.e. RA * cos(dec), at mean epoch (3) 76- 80 F5.1 mas e_DEdeg s.e. of Dec at mean epoch (3) 82- 85 F4.1 mas/a e_pmRA [1.6,24.0] s.e. prop mot in RA * cos(dec) 87- 90 F4.1 mas/a e_pmDE [1.6,24.1] s.e. of proper motion in Dec 92- 97 F6.3 mag BT [0.312,13.086]? Tycho BT magnitude (4) 99-103 F5.3 mag e_BT [0.001,0.3]? s.e. of BT (4) 105-110 F6.3 mag VT [0.283,15]? Tycho VT magnitude (4) 112-116 F5.3 mag e_VT [0.001,0.3]? s.e. of VT (4) 118-119 I2 --- Num [2,13] Number of positions used (5) 121 I1 --- q_pm [0,9] quality flag for proper motion (6) 123-128 I6 --- HD [1,359021]? HD identifier from TYC 130-135 I6 --- HIP [1,120404]? Hipparcos number from TYC 136-137 A2 --- CCDM CCDM component identifier from TYC (7) 139-144 F6.2 mas Plx [0.52,202.69]? parallax for HIP stars (8) 146 A1 --- dupflg [ DS] duplicity flag (9) 147 A1 --- varflg [ V] variability flag (10) 148 A1 --- ACTflg [ TX] ACT flag (11)
Note (1): The TYCID1 is the GSC region number, the TYCID2 is the running number within the region, the TYCID3 is a component identifier (normally 1). Some non-GSC running numbers were constructed for TYC. The recommended star designation contains a hyphen between the TYCID numbers, e.g. TYC 1-13-1. Note (2): The mean epochs are given in Julian years. Note (3): The standard errors given are for the mean epoch. They are in the range 1.0-117.1. The standard errors at some epoch, t, are obtained as e_RA(t)* = sqrt((f*e_RA*)2 + ((e_pmRA*)*(t-epRA))2 ) and e_DE(t) = sqrt((f*e_DE)2 + (e_pmDE*(t-epRA))2 ) A factor f=1.5 would give realistic standard errors for the majority of stars. This factor compensates for too small formal errors of positions in the Tycho Catalogue (Cf. Sect 18.4 of Vol 4 of "The Hipparcos and Tycho Catalogues", ESA SP-1200, 1997). Note (4): The BT and VT photometry is copied from the Tycho Catalogue. Approximate Johnson photometry may be obtained as: V = VT -0.090*(BT-VT) B-V = 0.850*(BT-VT) Consult Sect 1.3 of Vol 1 of "The Hipparcos and Tycho Catalogues", ESA SP-1200, 1997, for details. Note (5): Between 2 and 13 positions (TYC plus 1-12 AC positions) were used in the adjustment: Npos: 2 3 4 5 6 7 8 9 10 11 12 13 Stars: 20183 588096 312449 47150 18045 3169 742 217 81 33 14 3 Note (6): q_pm (0..9) gives twice the ratio of the estimated s.e. to the formal s.e. A large value may be taken as a warning. The value 9 marks proper motions deviating from HIP values by more than six combined standard errors. Separate values were computed for R.A. and Dec. Here the maximum value is given. The quality flag was computed prior to the adjustment of the standard errors (Cf Sect 3 of Hoeg et al. 1998). q_pm: 0 1 2 3 4 5 6 7 8 9 Stars 35082 271197 319970 183564 93971 45973 22662 11459 3494 2810 Note (7): The CCDM component identifier is only given for HIP stars. It is copied from field T51 of the Tycho Catalogue. Note (8): The parallax for HIP stars is copied from field H11 of the Hipparcos Catalogue, but only when it exceeds the standard error. The HIP parallax was NOT used in the construction of the TRC. Note (9): the duplicity flag is set for 16587 stars where duplicity was clearly indicated or suspected in the Tycho data, but not resolved. (T49 is D or S in TYC). Note (10): the variability flag is set for 18505 stars with known variability. (T47 set or T48='V' in TYC). Note (11): ' ' = also in ACT, proper motion agrees within 10 mas/yr in both coordinates; 'T' = only in TRC (39892 stars); 'X' = also in ACT, does not agree within 10 mas/yr (19104 stars).
Byte-by-byte Description of file: index.dat
Bytes Format Units Label Explanations
1- 6 I6 --- rec + Rec. numb. of 1st star in each region (1)
Note (1): The catalogue is sorted according to the GSC region numbers. The line i of the index file gives the record number in TRC of the first star in GSC region i. Line i+1 gives the record number +1 of the last star in GSC region i.

(End) Claus Fabricius [Niels Bohr Institute for Astronomy] 03-Apr-1998
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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