% perth70.tex - Documentation for Perth 70 catalog revised September 1992
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% Document Number: <docnum>
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% Written: September 1992 by William M. Owen, Jr. (JPL), Modified April 1993 by
% Nancy G. Roman
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\documentstyle [adc,11pt]{article}
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\newcommand{\dmv}{Documentation for the Computer-Readable Version }
\newcommand{\cat}{Perth 70: A Catalogue of Positions of 24900 Stars}
\newcommand{\abbr}{Perth 70}
\newcommand{\catref}{E. H{\o}g and J. von der Heide (1976)}
\newcommand{\pcatrefp}{E. H{\o}g and J. von der Heide 1976}
\newcommand{\docnum}{NSSDC/WDC-A-R\S 93-17}
%
\hyphenation{Durch-must-er-ung}
%
\begin{document}
%
\title{ \cat \\ Part B, Mean Values of the Observations}
\author{(\pcatrefp)}
\docauthor {William M. Owen, Jr. and Nancy G. Roman}
\docno{NSSDC/WDC-A-R\&S 93-17}
\date{April 1993}
\maketitle

\begin{abstract}

This {\em \cat} contains accurate positions and magnitudes of 24,871 reference
stars, mostly in the southern hemisphere, plus other useful data such as
approximate proper motions, radial velocities, and parallaxes. The Perth 70 is a
result of meridian circle observations made by the Hamburg Observatory
expedition to Perth as part of the international effort on Southern Reference
Stars (SRS).

The catalog described here provides the mean values for each star, including the
position, magnitude, and mean epoch of observation; the proper motions, however,
were neither observed nor recomputed from comparing the Perth positions to older
material.

\end{abstract}

\section{Introduction}

{\bf A copy of this document should be distributed with every copy of the
computer-readable catalog.}

\subsection{Description}

The {\em \cat\/} (\abbr ; \pcatrefp ) contains the results of meridian circle
observations of 24,871 stars carried out at Perth in the late 1960's and early
1970's.  This document describes the September 1992 version of ``Part B,'' which
contains the mean values of the observations in a form similar to that of
the printed catalog.  (``Part A,'' contains the nightly observations.)

The catalog is in 1 fixed-block file with 24,978 records of 150 bytes each. Some
107 circumpolar stars occupy two records each, one for observations at upper
culmination and one for observations at lower culmination, so the number of
records is greater than the number of stars.

The first part of each record presents the same information that is contained
in the printed catalog; the remaining information was not printed.

\subsection{Source Reference}

\begin{references}

\item E. H{\o}g and J. von der Heide (1976), {\em Perth 70: A Catalogue of
      Positions of 24900 Stars}, Abh.\ der Hamberger Sternwarte, Band IX.

\end{references}

\section{Structure}

\subsection{Each File as a Whole}

The \abbr\ consists of 1 file. A detailed description of the file is given in
the following section.

{\bf The following descriptions come from \catref\ }.


\subsection{Mean Values of the Observations (File 1 of 1)}

This file contains the mean values of the meridian circle observations
(position and magnitude) made at Perth, plus auxiliary quantities usually
taken from the preliminary version of the Southern Reference Stars (SRS)
catalog (Corwin, 1992).

A byte-by-byte description of the contents of each record is given in
Table~\ref{t:file1}. The suggested format given for each datum can be modified
depending upon usage; real (F) format specifications are given in many cases to
indicate clearly where decimal points should be located within the fields.
Missing data are denoted by blank-filled fields except for the standard errors
of one observation in $\alpha$ cos$\delta$ and in declination. In those fields,
missing data are indicated by ``0''. It may be desirable to read fields in which
data may be missing with an ``A'' format to avoid confusion with ``0''.

\begin{table} [ht]
\label{t:file1}
\centering
\begin{tabular}{ c c c l }                                           \hline
       &                  & Suggested     &                                   \\
 Bytes & Units            &   Format      & \multicolumn{1}{c|}{Data}         \\
\hline
  1-5  &                  &    I5         & Perth 70 catalog number.          \\
    6  &                  &    A1         & ``S'' for stars in the FK4
                                            Supplement.                       \\
  7-12 &  mag             &   F6.2        & V magnitude.                      \\
 14-15 &                  &    A2         & Spectral type, copied from
                                            preliminary SRS.                  \\
 16-28 & h,m,s            & 2I3,F7.3      & Right ascension, $\alpha$.        \\
    29 &                  &    A1         & Culmination flag.                 \\
 31-42 & $^\circ,{}',{}''$& A1,I2,I3,F6.3 &  Declination, $\delta$.           \\
 43-47 &yr${}-1900$       &   F5.2        & Mean epoch of observation in
                                            right ascension, $t_\alpha$.      \\
 48-52 &yr${}-1900$       &   F5.2        & Mean epoch of observation in
                                            declination, $t_\delta$.          \\
 53-55 &                  &    I3         & Number of observations of right
                                            ascension.                        \\
    56 &                  &    A1         & Deletion flag for right ascension.\\
 57-58 &                  &    I2         & Number of observations of
                                            declination.                      \\
    59 &                  &    A1         & Deletion flag for declination.    \\
 60-63 &${}''$            &   F4.2        & Residual in right ascension,
                                            $\Delta\alpha\cos\delta$.         \\
 64-68 &${}''$            &   F5.2        & Residual in declination,
                                            $\Delta\delta$.                   \\
 69-75 &s/yr              &   F7.5        & Proper motion in right ascension,
                                            $\mu_\alpha$.                     \\
 76-82 &${}''$/yr         &   F7.4        & Proper motion in declination,
                                            $\mu_\delta$.                     \\
 84-85 &                  &    A2         & Durchmusterung catalog identifier.\\
 87-94 &                  & A1,I2,I5      & Durchmusterung number (sign, zone,
                                            serial no.).                      \\
    96 &                  &    A1         & Type of star.                     \\
 97-102&                  &    I6         & Observing number for cross-reference
                                            with Part A.                      \\
103-105&                  &    I3         & Number of records in Part A for this
                                            star.                             \\
106-110&                  &    I5         & FK4 Supplement Catalog number.    \\
111-116& km/sec           &   F6.1        & Radial velocity.                  \\
117-120& ${}''$           &   F4.3        & Parallax.                         \\
121-123&                  &    I3         & Number of observations of magnitude.
                                                                              \\
    124&                  &    A1         & Deletion flag for magnitude.      \\
125-128&yr${}-1900$       &   F4.2        & Mean epoch of observation of
                                            magnitude.                        \\
129-131& ${}''$           &   F3.2        & Standard error of one observation in
                                            $\alpha\times\cos\delta$.         \\
132-134& ${}''$           &   F3.2        & Standard error of one observation in
                                            declination.                      \\
135-137&  mag             &   F3.2        & Standard error of one observation of
                                            magnitude.                        \\
138-141& ${}''$           &   F4.2        & Mean parallax factor in $\alpha$. \\
142-145& ${}''$           &   F4.2        & Mean parallax factor in $\delta$. \\
146-150& mag              &   F5.1        & $V$ magnitude from the preliminary
                                            SRS catalog.                      \\
\hline
\end{tabular}
\caption{File 1 Record Format}
\end{table}

\begin{definition}{30ex}

\item[Catalog number] This is copied from the preliminary SRS catalog. Stars
                  with numbers in the 30000's are in the FK4 catalog, with the
                  last four digits being the FK4 number. Stars with numbers in
                  the 40000's are in the Bright Star Catalog in the same format.
                  Stars with other numbers are program stars.
\item[V magnitude]   If the hundredths place (byte 12) is blank, the number
                  was copied from the preliminary SRS; otherwise, the magnitude
                  was observed at Perth.
\item[Equatorial coordinates]  Positions are referred to the system of the FK4
                  (equinox B1950.0) at the mean epoch of observation for each
                  coordinate for each star.
\item[Culmination flag]  This is blank except for circumpolar stars, which have
                 2 records, one marked `{\tt U}' for upper culmination
                 observations, and one marked `{\tt L}' for lower culmination
                 observations.
\item[Deletion flags] These fields contain `{\tt *}' if at least one measurement
                 (in right ascension, declination, or magnitude) was deleted.
\item[Residuals] These are the Perth position minus the position in the
                  preliminary SRS, corrected for proper motion to the mean
                  epoch of observation. The signs of the residuals are changed for
                  circumpolar stars observed at lower culmination.
\item[Proper motions] These are copied from the preliminary SRS; the Perth 70
                  positions were not used to compute them. For centennial proper
                  motions, use formats F7.3 and F7.2 for $\mu_\alpha$ and
                  $\mu_\delta$, respectively.
\item[Durchmusterung] The catalog identifier (bytes 84--85) is either
                  `{\tt BD}' for Bonner Durchmusterung,
                  `{\tt CD}' for Cordoba Durchmusterung, or
                  `{\tt CP}' for Cape Photographic Durchmusterung.
                  The zone is contained in bytes 87--89 (with the sign in byte
                  87), and the serial number, in bytes 90--94.
\item[Type of star] One of `{\tt P}' for program star, `{\tt F}'
                  for FK4 star, or `{\tt B}' for Bright Star Catalog star.
\item[Observing number] This number is included to enable cross references
                  between this catalog and Part A; it does not appear in the
                  printed catalog and should not be used as the principal
                  identification number.  Circumpolar stars have distinct
                  observing numbers for upper and lower culmination.
\end{definition}

\section{History}
\label{s:history}

The {\em \cat} (\abbr) was received by the Astronomical Data Center (ADC), NASA
Goddard Space Flight Center, from the Jet Propulsion Laboratory, in September
1992.

The file described here is the third version of the machine-readable version.
The original version, distributed by the CDS as catalog 1062B, gave prominence
to the preliminary SRS positions rather than the observed Perth positions.
Furthermore, the spectral type appeared as a coded integer rather than as a
character string.

The second version of the file was created by Susan E. Gessner and Lee E.
Brotzman of the ADC in December 1990.  The redundant catalog identifier was
removed from each record; blank columns reserved for updated proper motions
were also removed; and the Durchmusterung catalog identifier field was added.
At this time Nancy G. Roman discovered and corrected seven errors in the DM
identification numbers.  However, the rest of the data were untouched.

This version differs from the previous two versions in several respects. First,
and most important, the positions are those measured at Perth and published in
the printed catalog, {\em not\/} those of the preliminary SRS catalog. Second,
the spectral types now appear as character strings instead of as coded integers.
Finally, the first part of each record is very nearly identical to the printed
catalog itself, and fields that do not appear in the book are moved to the end
of each record. It is hoped that this latest revision will make the file that
much easier to use.

During the course of this revision it was discovered that two stars (SRS \#10601
and 16608) had incorrect DM catalog identifiers (BD instead of CD), and one star
(SRS \#3722), listed as ``BD 00 0,'' does not appear in any DM catalog. These
small errors have been corrected.


\subsection{References to the Documentation}

\begin{references}

\item Wayne H. Warren, Jr., ``Documentation for the Machine-Readable Version
of the Perth 70: A Catalog of Positions of 24900 Stars:  Tape B, Mean Values
of the Observations,'' NSSDC\slash WDC--A--R\&S 80--04, July 1980.

\item Susan E. Gessner and Lee E. Brotzman, ``Documentation
for the Machine-Readable Version
of the Perth 70: A Catalog of Positions of 24900 Stars:  Tape B, Mean Values
of the Observations,'' NSSDC\slash WDC--A--R\&S 80--04, revised December 1990.

\end{references}

\section{Additional Notes}
\label{s:notes}

The preliminary SRS positions may be recovered by
\begin{eqnarray*}
\alpha_{\rm SRS} &=& \alpha_{\rm Perth} - \mu_\alpha(t_\alpha - 1950.0)
 \mp(\Delta\alpha\cos\delta)/ 15 \cos \delta_{\rm SRS},\\
\delta_{\rm SRS} &=& \delta_{\rm Perth} - \mu_\delta(t_\delta - 1950.0)
 \mp \Delta\delta,\\
\end{eqnarray*}
where the symbols are defined in Table~\ref{t:file1};
the plus sign is taken only for stars observed at lower culmination.
The factor 15 in the first equation emphasizes that $\Delta\alpha\cos\delta$
is tabulated in arc seconds whereas right ascension is customarily expressed
in units of time.

The spectral types are always those of the printed catalog.  Two stars must be
mentioned specifically: $\gamma^2$ Velorum (SRS \#30309) and $\chi$ Cygni
(SRS \#44262).  The first, a Wolf-Rayet star (type WC), is listed in the FK5 as
``Oap'' (the HD designation) and appears here as ``O0.''  The second,
a Mira Ceti-type pulsating variable, spectral type ``S7ev,''
appears here as ``M7.''

\end{document}
