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I/238A      Yale Trigonometric Parallaxes, Fourth Edition  (van Altena+ 1995)

The General Catalogue of Trigonometric Stellar Parallaxes, Fourth Edition Van Altena W.F., Lee J.T., Hoffleit E.D. <Yale University Observatory (1995)> =1995GCTP..C......0V
ADC_Keywords: Parallaxes, trigonometric Description: This is a completely revised and enlarged edition of the General Catalogue of Trigonometric Stellar Parallaxes containing 15,994 parallaxes for 8,112 stars published before the end of 1995. In this Fourth Edition, 1,722 (27%) new stars have been added to those contained in the previous edition by Jenkins (1963). The mode of the parallax accuracy for the newly added stars (0.004" s.e.) is considerably better than in the previous editions (about 0.016"). Approximately 2300 stars are not in the Hipparcos Catalog. The catalog contains equatorial coordinates in the system of the FK4 for 1900, the total proper motion and its position angle, the weighted average absolute parallax and its standard error, the number of parallax observations, quality of interagreement of the different values, the visual magnitude and various cross identifications with other catalogs. Auxiliary information is listed, including UBV photometry, MK spectral types, data on the variability and binary nature of the stars, and miscellaneous information to aid in determining the reliability of the data. Introduction: The 1900 equinox has been maintained to avoid assigning yet another star number and avoid potential errors, since the 1900 based numbers have been used in the Notes and elsewhere in the Catalogue. For each star, the printed catalog contains a reference to the source of publication of the individual parallax The relative parallaxes are corrected to absolute parallax using newly computed corrections that are based on an improved model of the Galaxy. In the Introduction to the printed Catalogue, an analysis of the resulting absolute parallaxes has been made to study the accidental and systematic errors of the parallaxes. Those results provide a "system" for the Catalogue which then yields weighted absolute parallaxes for each star. A preliminary version I/174 of this catalog was previously archived in the Astronomical Data Centers and was included on the first ADC CD-ROM. In this final version the authors have revised the weighting system, and included newly published parallaxes, photometry and spectral types for most of the stars. The weighted mean parallaxes of many stars will be found to differ from those in the preliminary version due to changes in the weighting system, revisions to the default reference star magnitudes and the addition of new parallaxes. The file "errata.dat", added in August 2001, was supplied by Erkki U. Vilkki; it contains rectifications and additions to the General Catalogue of Trigonometric Stellar Parallaxes. Majority of additions are from the Lowell proper motion survey. In the double star information designations were rectified according to the last edition of the Washington Double Star WDS catalog. The following CD-ROMs were used: ADS Selected Astronomical Catalogs, Vol. 1, Vol. 2, and Vol. 3 (FITS versions), the Guide Star Catalog (version 1.1), HyperSky Data Bank, and Guide. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file picat.dat 132 8994 The data file source.dat 148 58 Explanation of the source codes errata.dat 132 2134 *Corrections and additions by Erkki U. Vilkki
Note on errata.dat: this file was added in August 2001
Byte-by-byte Description of file: picat.dat
Bytes Format Units Label Explanations
1 A1 --- f_GCTP [*] Indicates a note in file "errata.dat" 2- 8 F7.2 --- GCTP *Catalog number 10- 11 I2 h RAh ?Right ascension hours (1900.0) 13- 14 I2 min RAm ?Right ascension minutes (1900.0) 16- 19 F4.1 s RAs *?Right ascension seconds (1900.0) 21 A1 --- DE- Declination sign 22- 23 I2 deg DEd ?Declination degrees (1900.0) 25- 26 I2 arcmin DEm ?Declination minutes (1900.0) 28- 29 I2 arcsec DEs ?Declination seconds (1900.0) 30 A1 --- u_RAm *[:C] : = lower precision position 32- 36 F5.2 mag Vmag *?V magnitude or other magnitude 37 A1 --- n_Vmag P indicates blue passband 39- 43 F5.2 mag B-V ?B-V color 45- 49 F5.2 mag U-B ?U-B color 51 A1 --- r_Vmag Source code for photometry 53- 62 A10 --- MK *Spectral type 63 A1 --- r_MK Source code for spectral type 64 A1 --- comp *Double star component 65- 73 A9 --- var *Variable star name 74- 77 I4 --- HR *?HR number 78 A1 --- supp [S] S=in Hoffleit BSS Cat. V/36 79- 85 A7 --- HD HD number and component 86- 95 A10 --- DM *DM identification and component 96-106 A11 --- name Star name 107-112 F6.3 arcsec/yr pm ?Total Proper motion 114-116 I3 deg pmPA ?Proper motion position angle 118-124 F7.4 arcsec pi ?Weighted absolute parallax 126-128 I3 0.1mas e_pi ?Standard error of parallax 130 A1 --- q_pi *[ GFPX]Quality of interagreement 131-132 I2 --- o_pi *?Number of parallax observations
Note on GCTP: There are nine stars for which no data are given. They were previously misidentified and had no parallaxes available. They have been retained for completeness in the star numbers. These are: 268.00, 1810.10, 1965.00, 2129.10, 3023.00, 3686.10, 4132.00, 4728.00, and 5699.10. There are no entries in the records for these stars except the identifications. Note on RAs, u_RAm: The number of significant figures indicates the accuracy of the position. No explanation was given to the flag 'C' in the u_RAm column Note on Vmag: The magnitudes of stars with two digits following the decimal point are photoelectric V magnitudes; the remaining magnitudes are lower accuracy visual magnitudes or miscellaneous other types. Details are given in the printed Catalogue. Note on MK: The MK type is given if it exists. Note on var: A number beginning with S is a New Suspected Variable number (see Cat. II/140) Note on HR: From Hoffleit, E.D. and Warren, W., 1988 revised in the electronic version (see cat. V/50) Note on comp: M indicates photometrically unresolved components Note on DM: B = Bonner Durchmusterung (catalogs I/119, I/122) C = Cordoba Durchmusterung (catalog I/114) P = Cape Photographic Durchmusterung (catalog I/108) Note on q_pi: G = good F = fair P = poor X = discordant Note on o_pi: Number of parallax observations included in the weighted average parallax
Byte-by-byte Description of file: source.dat
Bytes Format Units Label Explanations
1- 3 A3 --- type [ubvsp ] type of source, "ubv" or "sp" 5 A1 --- code Code for source (ubv or sp) 7-148 A142 --- source Source reference.
Byte-by-byte Description of file: errata.dat
Bytes Format Units Label Explanations
1- 7 F7.2 --- GCTP Designation in picat.dat 8- 10 A3 --- m_GCTP Multicplicity index on GCTP 12-132 A121 --- Text Text of note
Acknowledgement: We thank Dr. Van Altena for sending us the electronic version of the catalog and thank, particularly, Dr. John T. Lee for extensive help in providing the necessary additional information. History: * 14-Nov-1996: Documentation and Catalogue prepared by Nancy Grace Roman [ADC/SSDOO] * 10-Aug-2001: The file "correct.htm" was supplied by Erkki U. Vilkki to CDS. The file "errata.dat" is a direct derivation of "correct.htm", and the flag in column 1 of the file "picat.dat" was added to the stars appearing in the errata.
(End) Nancy Grace Roman [ADC/SSDOO], Francois Ochsenbein [CDS] 11-Aug-2001
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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