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I/238A Yale Trigonometric Parallaxes, Fourth Edition (van Altena+ 1995)
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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
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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:
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FileName Lrecl Records Explanations
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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
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Note on errata.dat: this file was added in August 2001
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Byte-by-byte Description of file: picat.dat
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Bytes Format Units Label Explanations
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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
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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
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Byte-by-byte Description of file: source.dat
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Bytes Format Units Label Meaning
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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.
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Byte-by-byte Description of file: errata.dat
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Bytes Format Units Label Explanations
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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
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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
<evilkki@worldonline.fr>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.
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(End) Nancy Grace Roman [ADC/SSDOO], Francois Ochsenbein [CDS] 11-Aug-2001