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V/61                Almagest  (Ptolemy's Star Catalog)
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The Almagest: Ptolemy's star catalogue (years 127-141)
     Ptolemy C.       
    <translation by Manitius K.,ed. B.G. Teubner, Leipzig (1913)>
     Jaschek C.
    <Bull. Inform. CDS 33, 125 (1987)>
    =1987BICDS..33..125J
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ADC_Keywords: Historical catalog

Description:
    This catalogue is the machine readable version of the star catalogue
    given by Claudius Ptolemy in his book called usually the Almagest. It
    is based upon its translation by K. Manitius (ed. B.G. Teubner,
    Leipzig 1913).

    The table reproduces the values given in book VII, chapter V, namely
    Identification, name, longitude, latitude and magnitude. To facilitate
    its use the following changes were made:

    Identifications : the numbers of Ambronn's catalogue (used by
    Manitius) were replaced by the numbers in the Bright Star Catalogue
    (D. Hoffleit and C. Jaschek - Fourth edition - Yale University
    Observatory 1982) which are commonly used today.

    Name : we have kept the Bayer names but omitted the description given
    by Manitius (for instance alpha UMi = that of the end of the tail).
    Whenever a disagreement exists concerning the identification of a
    given star, this is signaled by a "D" (disagreement) in the notes
    (last column). The list of disagreements was taken from Werner H. and
    Schmeidler F., "Synopsis der Nomenklatur der Fixsterne" - Wissensch.
    Verlags-Gesellschaft Stuttgart (1986) where the interested reader
    may find detailed references. Most of the disagreements stem from the
    work of Peters and Knobel, Washington 1915.

    Longitude : the Ptolomean longitudes were converted into the commonly
    used longitudes by adding 0 to longitudes in Aries, 30 to those in
    Taurus, etc. Longitudes vary thus between 0 and 360 .

    Latitudes : no change from Ptolemy.

    Magnitudes : no change from Ptolemy.

    Notes : "D" stands for disagreements over identifications, see above.

    With the publication of a computer readable version of this catalogue
    we hope to satisfy a long standing need. We also pay in this way our
    debt of gratitude toward the astronomer who produced the most used
    catalogue in the history of astronomy - for more than fourteen
    centuries it was THE catalogue by definition. It seems only
    appropriate that a data center, who is in a long way a descendant of
    such an enterprise, includes the catalogue in its collection.

See also:
    V/50   (The Bright Star Catalogue)

File Summary:
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 FileName    Lrecl    Records    Explanations
--------------------------------------------------------------------------------
ReadMe          80          .    This file
north.dat       47        360    Northern part (except Zodiacal stars)
south.dat       47        317    Southern part (except Zodiacal stars)
zod_n.dat       47        167    Zodiacal stars, North
zod_s.dat       47        183    Zodiacal stars, South
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Byte-by-byte Description of file: north.dat, south.dat, zod_n.dat, zod_s.dat
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   Bytes Format  Units   Label    Explanations
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   1- 16  A16    ---     Const    Constellation name
  18- 21  I4     ---     HR       [0/9110]? Bright Star Number, 0 if cluster
  22- 24  A3     ---     m_HR     Second HR number for binaries
  26- 27  I2     ---     Seq      Number in constellation
  29- 31  I3     deg     Lon.d    Ptolemean (ecliptic) longitude (degrees) (1)
  33- 34  I2     arcmin  Lon.m    Ptolemean (ecliptic) longitude (minutes) (1)
      36  A1     ---     Lat-     Ptolemean (ecliptic) latitude (sign)
  37- 38  I2     deg     Lat.d    Ptolemean (ecliptic) latitude (degrees)
  40- 41  I2     arcmin  Lat.m    Ptolemean (ecliptic) latitude (minutes)
  43- 45  F3.1   mag     Mag      [1/8] Ptolemean magnitude (2)
      47  A1     ---     Disag    [D] 'D' if a disagreement exists
                                    concerning identification
--------------------------------------------------------------------------------
Note (1): the Ptolomean longitudes were converted by adding 30deg in Taurus
    etc (see Description).
    The epoch of observation is compared to -128 by Grasshoff G., 1990,
    "The history of Ptolemy's Star Catalogue", ed. G.J. Toomer,
    Springer-Verlag (ISBN 0-387-97181-5)
Note (2): the Ptolomean magnitudes are only integer numbers between 1 and 6;
    the values "7." correspond to "faint", and "8." for "nebula".
    The decimal value "m.3" (m between 1 and 4) indicate original "(m)-(m+1)"
    The decimal value "m.7" (m between 1 and 4) indicate original "(m-1)-(m)"
    Examples:   "2.7" correspond to original  "3-2"
                "3.3" correspond to original  "3-4"

Historical Notes:
  * 1987: Keypunched at CDS, Strasbourg;
          original technical note prepared by O.Yu. Malkov
  * 17-Jul-1995: Documentation standardized at CDS
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(End)                                     Francois Ochsenbein [CDS]  17-Jul-1995