
\documentstyle [adc,11pt]{article}
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\newcommand{\dmv}{Documentation for the Computer-Readable Version}
\newcommand{\cat}{The General Catalogue of 33342 Stars for the Epoch 1950}
\newcommand{\abbr}{GC}
\newcommand{\catref}{Boss 1937}
\newcommand{\pcatref}{Boss, B.}
\newcommand{\docnum}{NSSDC/WDC-A-R\&S 93-29}
\newcommand{\um}{$\mu m$}
\parindent 0pt
\parskip 11pt
%
\begin{document}
%
\title{\cat}
\author{(\catref)}
\docauthor{Nancy G. Roman and Wayne H. Warren Jr.}
\docno{NSSDC/WDC-A-R\&S 93-29}
\date{July  1993}
\maketitle

\begin{abstract}

A revised and corrected version of the machine-readable catalog has been
prepared. Cross identifications of the {\em GC} stars to the HD and DM catalogs
have
been replaced by data from the {\em SAO-HD-GC-DM Cross Index} (Roman et al.
1983), including component identifications for multiple SAO entries
having identical DM numbers in the SAO Catalog, supplemental Bonner
Durchmusterung stars (lowercase letter designations) and codes for multiple HD
stars. Additional individual corrections have been incorporated based upon
errors found during analyses of other catalogs. Most of these changes had
already been incorporated into a previously available version (Roman \& Warren
1983); but the probable errors of the positions and proper motions, included in
the original published catalog, were not available in machine-readable form
until 1992. These were added at that time to produce a new, computer-readable
catalog. Finally, in this version decimal points have been aligned for all but
a very few of the secular variations and third terms. These quantitites are
given with the same precision as in the printed catalog, and the coded spectral
types have been omitted.

\end{abstract}

\section{Introduction and Source Reference}

\subsection{Introduction}

The machine-readable version of the {\em General Catalogue of 33342 Stars for
the Epoch 1950} (GC, Boss 1937) includes {\em Henry Draper Catalogue} (HD,
Cannon \& Pickering 1918-1924) and Durchmusterung (DM) numbers for all stars,
although the published version gives only one or the other. The Astronomical
Data Center has produced a new version of the cross index among {\em Smithsonian
Astrophysical Observatory Catalog} (SAO, Smithsonian Astrophysical Observatory
Staff 1966), HD, GC and DM catalog numbers. Since most of the errors of which we
are aware in the first machine-readable (1980) version of the GC occurred in
either the DM or HD number, these entries were completely replaced on the basis
of the revised cross index. The cross index also identifies components of
multiple stars, provides small letter designations for supplemental stars in the
{\em Bonner Durchmusterung}, and includes a code to indicate that the spectrum
is likely to be blended and, if so, whether the entry is for the brighter or
fainter component. A total of 1186 changes was made to 1091 data records in
1985. A small number of errors have been corrected since. Probable errors for
the positions and centennial proper motions have now been included.

This document describes the machine-readable version of the corrected and edited
GC as it is currently being distributed by the Astronomical Data Center. It is
intended to enable users to read and process the data without the common
problems and guesswork often associated with such a task. {\bf A copy of this
document should be distributed with any machine-readable version of the
catalog.}

\subsection{Source Reference}

Boss, B. 1937, General Catalogue of 33342 Stars for the Epoch 1950, Carnegie
  Inst. Washington, Pub. 468 (Washington, Carnegie Institution of
  Washington)

\section{File Contents}

A byte-by-byte description of the contents of the machine-readable Boss
{\em General Catalogue} is given in Table 1.  A suggested FORTRAN format
specification for reading each datum is given and can be modified depending
upon usage.  Caution is advised when substituting format specifications,
since some data fields contain character data and others are blank when data
are absent.  Alternate format specifications are given in parentheses.
Additional information and remarks are given in the notes to Table 1.

\begin{table} [h]
\begin{center}
\begin{tabular}{ c c c l }
\multicolumn{4}{c}{\em General Catalogue of 33342 Stars for the Epoch 1950}
          \\
\hline
         &         &  Suggested  &                                          \\
Byte(s)  & Units   &   Format    &  Description                             \\
\hline
  1-  5  &  ---    &    I5       &  GC number.                              \\
         &         &             &                                          \\
  6- 10  &  mag    &    F5.2     &  Magnitude (``VAR'' given as 9999;       \\
         &         &             &  see note 1)                             \\
         &         &             &                                          \\
 11- 14  &  ---    &    A4       &  Spectral type                           \\
         &         &             &                                          \\
 16- 17  & hours   &    I2       &  Right ascension, equinox 1950.0         \\
         &         &             &                                          \\
 18- 19  &  min    &    I2       &  Right ascension                         \\
         &         &             &                                          \\
 20- 25  &  sec    &    F6.3     &  Right ascension                         \\
         &         &             &                                          \\
 26- 29  & years   &    F4.1     &  Epoch of right ascension observations   \\
         &         &             &  (see note 4)                            \\
         &         &             &                                          \\
 30- 36  & arcsec  &    F7.4     &  Annual variation in R.A. (see note 3)   \\
         &         &             &                                          \\
 37- 44  & arcsec  &  A8(F8.4)   &  Secular variation in R.A. (see note 3)  \\
         &         &             &                                          \\
 45- 52  & arcsec  &  A8(F8.3)   &  Third term in R.A. (see note 3)         \\
         &         &             &                                          \\
 53- 58  &  sec    &    F6.4     &  Proper motion in R.A                    \\
         &         &             &                                          \\
     59  &  ---    &    A1       &  Sign of declination, equinox 1950.0     \\
\hline
\end{tabular}
\caption{File 1 Format}
\end{center}
\label{T:format}
\end{table}


\begin{table}  [h]
\begin{center}
\begin{tabular}{ c c c l }
\multicolumn{4}{c}{\em General Catalogue of 33342 Stars for the Epoch 1950}
\\
\hline
         &         &             &                                          \\
 60- 61  &  deg    &    I2       &  Declination                             \\
         &         &             &                                          \\
 62- 63  & arcmin  &    I2       &  Declination                             \\
         &         &             &                                          \\
 64- 68  & arcsec  &    F5.2     &  Declination                             \\
         &         &             &                                          \\
 69- 72  & years   &    F4.1     &  The mean epoch of declination           \\
         &         &             &  observations (note 4)                   \\
         &         &             &                                          \\
 73- 79  & arcsec  &    F7.3     &  Annual variation in declination         \\
         &         &             &                                          \\
 80- 86  & arcsec  &  A7(F5.3)   &  Secular variation in declination        \\
         &         &             &                                           \\
 87- 93  & arcsec  &  A7(F4.2)   &  Third term in declination                \\
         &         &             &                                            \\
 94- 99  & arcsec  &    F6.3     &  Proper motion in declination. The values  \\
         &         &             &  are based on the Newcomb values of        \\
         &         &             &  precession                               \\
         &         &             &                                            \\
    100  &  ---    &    A1       &  Remarks (see note 2)                      \\
         &         &             &                                            \\
101-102  &  ---    &    A2       &  Durchmusterung (DM) identification (BD =  \\
         &         &             &  Bonner Durchmusterung; CD = Cordoba       \\
         &         &             &  Durchmusterung; CP = Cape Photographic    \\
         &         &             &  Durchmusterung).  All DM fields are blank \\
         &         &             &  if no DM identification is present       \\
         &         &             &                                            \\
    103  &  ---    &    A1       &  Sign of DM zone                          \\
         &         &             &                                            \\
104-105  &  ---    &    I2 (A2)  &  DM zone                                  \\
         &         &             &                                            \\
106-110  &  ---    &    I5 (A5)  &  DM number                                \\
         &         &             &                                            \\
111-112  &  ---    &    A2       &  Component identification if two or more   \\
         &         &             &  SAO stars have the same DM number.  For   \\
         &         &             &  southern stars components may appear in  \\
         &         &             &  different catalogs                       \\
         &         &             &                                            \\
\hline
\end{tabular}
\caption{File 1 Format (continued)}
\end{center}
\label{T:format}
\end{table}


\begin{table}    [h]
\begin{center}
\begin{tabular}{ c c c l }
\multicolumn{4}{c}{\em General Catalogue of 33342 Stars for the Epoch 1950}  \\
\hline
Byte(s)  & Units   &   Format    &  Description                               \\
\hline
    113  &  ---    &    A1       &  Lowercase letters for BD supplemental     \\
         &         &             &  stars (Warren \& Kress 1980)              \\
         &         &             &                                            \\
114-120  &  deg    &    F7.3     &  Galactic longitude, l\small$_{II}$        \\
         &         &             &                                            \\
121-127  &  deg    &    F7.3     &  Galactic latitude, b\small$_{II}$         \\
         &         &             &                                            \\
128-133  &  ---    &    I6       &  {\em Henry Draper Catalogue} number (blank\\
         &         &             &  for stars without HD numbers)             \\
         &         &             &                                            \\
    134  &  ---    &    I1       &  HD code.  0 for single stars or brighter  \\
         &         &             &  components of doubles with difference in  \\
         &         &             &  visual magnitude $>0.3$ mag. For doubles  \\
         &         &             &  with difference in visual magnitude       \\
         &         &             &  $\geq 0.3$ mag, 1 designates the brighter \\
         &         &             &  component, not necessarily A, and 2 the   \\
         &         &             &  fainter one.  9 indicates that two        \\
         &         &             &  successive HD numbers (HD and HD+1) refer \\
         &         &             &  to the same SAO star.                     \\
         &         &             &                                            \\
135-138  & arcsec   &   F4.3     &  Probable error in R.A. at epoch.  Preci-  \\
         &          &            &  sion varies for all p.e. fields;  where   \\
         &          &            &  precision is lower, succeeding bytes      \\
         &          &            &  are blank.                                \\
         &          &            &                                            \\
139-142  & arcsec   &   F4.2     &  Probable error of centennial proper       \\
         &          &            &  motion in R.A.                            \\
         &          &            &                                            \\
143-145  & arcsec   &   F4.3     &  Probable error in dec. at epoch           \\
         &          &            &                                            \\
147-150  & arcsec   &   F4.2     &  Probable error of centennial proper       \\
\hline
\end{tabular}
\caption{File 1 Format (concluded)}
\end{center}
\label{T:format}
\end{table}

\clearpage

\pagebreak
\begin{center}
\large{Notes to Table 1}
\end{center}
\vspace{1ex}
\subsubsection{Magnitude}

All magnitudes are given to two decimal places in the computer-readable version.
Magnitudes underlined in the published version of the catalog are not indicated
on the computer-readable version.

\subsubsection{Remarks}
\vspace{1ex}
0 = No remark given~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\linebreak
1 = Spectrum given~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\linebreak
2 = Aitken or Innes number given~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\linebreak
3 = Aitken or Innes number given with each component having a separate GC number
\linebreak
4 = Other information given~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\linebreak
5 = 1+2~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\linebreak
6 = 1+3~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\linebreak
7 = 1+4~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\linebreak
8 = 2+4~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\linebreak
9 = 3+4~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\linebreak
- = 1+2+4~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\linebreak
+ = 1+3+4~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\linebreak

\subsubsection{Annual Variation}

The annual variations in right ascension and declination are given to six
significant figures of which a minus sign is one. If more than one digit and a
minus sign precede the decimal, the corresponding number of digits is dropped at
the end of the number, e.g., +3.0588,~-1.1487,~+38.907, but
\linebreak -26.814,~+103.657.
However, the latter is an exception. If the last digit of a seven significant
figure value is read as zero, it is almost certainly blank.

The secular variations in right ascension and declination are given to four
and three significant digits, respectively, in addition to the sign.

The third term is given to three and two significant figures in right
ascension and declination, respectively.

If the last digit of the secular variation or the third term is read
as zero, it is almost certainly blank.  This can be confirmed by
reading the values with an A format.

\subsubsection{Epoch}
The first two digits of the year are omitted.  Thus, 98.8 should be read 1898.8
and 05.3 should be read 1905.3.


\begin{table}
\centering
\begin{tabular}{ c c l }
\multicolumn{3}{c}{List of Corrections from Earliest Version}   \\
\hline
 Field    &Format&  Value        \\
\hline                           \\
 2 -  6   & I5   &  GC Number    \\
10 - 16   & A7   &  Field        \\
18 - 27   & A10  &  Old value    \\
29 - 41   & A13  &  New value    \\
\hline
\end{tabular}
\caption{File 2 Format }
\label{T:format2}
\end{table}

\section{File Characteristics}

The information in Table 5 is sufficient for a user to describe the indigenous
characteristics of the present version of the GC to a computer.

\begin{table} [h]
\centering
\begin{tabular}{ c l c c r }
\multicolumn{5}{c}{\em \cat}                                                  \\
\hline
       &                               &Record  &             & Number of  \\
File   & Subject                       &Length  & Format      & Records
\\
\hline
  &                                    &        &             &             \\
1 & Data file                          &   150  & Fixed block & 33342       \\
2 & Changes since the 1980 catalog     &    41  & Fixed block &  1205       \\
\hline
\end{tabular}
\caption{File Characteristics}
\label{T:files}
\end{table}

\section{Remarks and Modifications}

The 1983 edition of the tape version of the GC is based on a machine-readable
version obtained from the U.S. Naval Observatory and modified by Theresa A. Nagy
in 1980. The primary changes to the 1983 version are reformatting to eliminate
most of the blank fields and the substitution of HD numbers, duplicity codes
for the HD numbers, and DM numbers from the {\em SAO-HD-GC-DM Cross Index}. The
latter includes both the DM designations and letters to indicate binary
components and supplemental stars in the BD. DM designations have also been
added for the few stars not included in the SAO. HD numbers in the cross index
were compared with those originally in the GC, discrepancies were checked, and
both catalogs corrected appropriately. The 1983 edition was augmented by the
addition of probable errors for the positions and centennial proper motions in
1992. The p.e. data were punched at the Royal Greenwich Observatory under the
direction of R. H. D. Swifte. Finally, in the current version, ending zeros in
the secular variation and third term have been dropped to preserve the precision
in the printed catalog. Decimal points and signs for these values have been
aligned except for a few stars for which the values are too large to fit if the
decimals are aligned. The coded spectral types have been omitted since
alphanumeric computers are now used generally. At some point, the letter
subtypes in the spectra were translated to numbers. (E.g. Mb became M3.) These
have now been converted back to the way they are given in the printed catalog.
However, the types which have been added for spectral type fields containing an
asterisk have been retained.

A table of all changes made since the first machine-readable version is included
in file 2 except for general changes, such as the addition of the probable
errors, changes to lowercase letters when appropriate, and the removal of the
coded spectra types.

The following quantities were not included (and have not been added) in the
machine-readable version of the catalog but are in the published version:

1.  The centennial increment of the proper motion in right ascension.

2.  The centennial increment of the proper motion in declination.

3.  Remarks.  However, there is a numerical code in byte 95 that indicates
    the presence of a remark.  This code also indicates the type of
    information contained in the remark if there is one (see notes to
    Table 1.)

The following quantities have been added to the machine-readable version of
the catalog but are not contained in the published version:

1.  Galactic longitude (degrees)

2.  Galactic latitude (degrees)

3.  DM numbers

\section{Acknowledgment}

We thank R. H. D. Swifte of the Royal Greenwich Observatory for providing in
machine-readable form the probable errors that have been added to produce the
1985 version of the GC. We also thank Miss Susan Gessner and Mr. Lee Brotzman
for calling our attention to some improper characters in the spectrum fields and
the extra zeros that had been appended to the secular variations and third
terms.




\section{References}

\begin{references}

\item Boss, B. 1937, General Catalogue of 33342 Stars for the Epoch 1950,
Carnegie Institution of Washington, Pub. 468 (Washington, Carnegie Institution
of Washington)

\item Cannon, A. J., and Pickering, E. C. 1918-1924, Ann. Astron. Obs. Harvard
College, 91-99

\item Morgan, H. R. 1952, Astron. Papers Amer. Ephemeris, 13, Part III

\item Nagy, T. A. 1980, Documentation for the Machine-Readable Version of the
General Catalog, R-SAW-4/80-08, Systems and Applied Sciences Corporation,
(Greenbelt, MD, Goddard Space Flight Center)

\item Ochsenbein, F., Bischoff, M., and Egret, D. 1981, Astron. Astrophys.
Suppl., 43, 259

\item Roman, N. G., and Warren, W. H. Jr. 1983, Documentation for the Machine-
Readable Version of the General Catalogue of 33342 Stars for the Epoch 1950,
NSSDC/WDC-A-R\&S 83-07 (Greenbelt, MD, Goddard Space Flight Center)

\item Smithsonian Astrophysical Observatory Staff 1966, Pub. of the Smithsonian
Institution of Washington, D. C., No. 4652 (Washington: Smithsonian Institution)

\item Warren, W. H. Jr., and Kress, K. 1980, Astron. Data Center Bull., 1, 19

\end{references}

\end{document}






