File Summary:
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 FileName           Lrecl  Records   Explanations
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ReadMe                 80        .   This file
lac_notes.dat                        Issues in source catalogs [CA], [EA], [EN]
lac_data.dat           50     1942   Lacaille's catalog of 1942 stars from [CA]
lac_corr.dat           39       11   Lacaille's catalog of 1942 stars from [CA]
obs_data.dat           56     1935   Lacaille's observations from [EA]
neb_data.dat           24       42   Lacaille's nebulous objects from [EN]
lac_ident.dat         120     2021   Cross-identifications of Lacaille's stars
lac_bids.dat                         Modern letter assignments to [CA] stars
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Byte-by-byte Description of file: lac_data.dat lac_corr.dat
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   Bytes Format Units   Label   Explanations
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   1-  4  I4    ---     LNo     [1-1942] Number in this catalog
       5  A1    ---     Note    [+]? Warning about this entry (1)
   6-  8  A3    ---     Con     Constellation abbreviation
       9  A1    ---     Inf     [~]? ~ if 'informis' (2)
  10- 12  A3    ---     Con_    ?Second constellation abbreviation (3)
  14- 16  A3    ---     Let     ?Letter in constellation
  18- 20  A3    ---     Mag     Magnitude or nebulosity type (4)
  22- 24  I3    deg     RA.d    Right ascension 1750 (degrees)
      25  A1    ---     Ref     [*]? Reference star marker (5)
  26- 27  I2    arcmin  RA.m    Right ascension 1750 (minutes)
  29- 30  I2    arcsec  RA.s    Right ascension 1750 (seconds)
  32- 33  I2    deg     DE.d    Declination south 1750 (degrees)
  35- 36  I2    arcmin  DE.m    Declination south 1750 (minutes)
  38- 39  I2    arcsec  DE.s    Declination south 1750 (seconds)
  41- 50  A10   ---     Name    ?Star name
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Note (1): a '+' here indicates a that there is an issue with this entry, with
    an explanation in lac_notes.dat.

Note (2): this field contains the '~' character when the 'Constellationum
    Nomina' column indicates that the star is "informis" (outside of figure, as
    in Ptolemy's catalog) between two constellations, e.g., 'Inf. int. Oct. &
    Mens.'.  In this case, the next field has the abbreviation of the second
    constellation.

Note (3): this field contains the abbreviation of the second constellation when
    the 'Constellationum Nomina' column indicates that the star is either
    "informis" between two constellations or simply between two constellations
    (e.g., 'Inter Phoen. & Tucan.').

Note (4): magnitude is either an integer between 1 and 6 or one of
    neb "a nebulosity or remarkable whiteness in the sky, such as a faint comet
        would appear" ('neb.' in the catalog),
    En  "a star surrounded or accompanied by a nebulosity" ('E neb.' in the
        catalog),
    An  "a cluster of small stars close together, that appear to the naked eye
        as a nebulosity in the sky" ('A neb.' in the catalog),
    GAn "a considerable cluster of such stars" ('G.A. neb.' in the catalog),
    AEn "a cluster of small stars wrapped in a nebulosity" ('AE neb.' in the
        catalog).

Note (5): Lacaille places a '*' here for stars that have been observed with
    maximal precision and served as reference to determine the positions of the
    others.

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Byte-by-byte Description of file: obs_data.dat
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   Bytes Format Units   Label   Explanations
--------------------------------------------------------------------------------
   1-  4  I4    ---     ONo     [1-1935] Observation number
       5  A1    ---     Note    [+]? Warning about this entry (1)
   6-  8  A3    ---     Con     ?Constellation abbreviation
  10- 12  A3    ---     Let     ?Letter in constellation
  14- 16  A3    ---     Mag     Magnitude or nebulosity type (2)
  18- 19  I2    h       RA.h    Right ascension (hours)
      20  A1    ---     Ref     [*]? Reference star marker (3)
  21- 22  I2    min     RA.m    Right ascension (minutes)
  24- 25  I2    s       RA.s    Right ascension (seconds)
  27- 28  I2    deg     DE.d    Declination south (degrees)
  30- 31  I2    arcmin  DE.m    Declination south (minutes)
  33- 34  I2    arcsec  DE.s    Declination south (seconds)
  36- 38  A3    ---     Month   Month of the observation
  40- 41  I2    ---     Day     Day of the month of the observation
  43- 45  I3    ---     Page    ?Page number (4)
  47- 56  A10   ---     Name    ?Star name
--------------------------------------------------------------------------------

Note (1): a '+' here indicates a that there is an issue with this entry, with
     an explanation in lac_notes.dat.

Note (2): magnitude is either an integer between 1 and 6 or one of 'neb', 'En',
    'An', 'GAn', 'AEn'.  See Note (4) for lac_data.dat.

Note (3): reference stars have a '*' here.  See Note (5) for lac_data.dat.

Note (4): lines in [EA] are not numbered.  The page number is mentioned for the
    first entry of each page to make it easier to match the observations file
    with the original document.

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Byte-by-byte Description of file: neb_data.dat
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   Bytes Format Units   Label   Explanations
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   1-  3  A3    ---     Set     Object class (I, II, or III)
       4  A1    ---     Delim   [.] Delimiter
   5-  6  I2    ---     Num     Object number within the class
   8-  9  I2    h       RA.h    Right ascension 1750 (hours)
  11- 12  I2    min     RA.m    Right ascension 1750 (minutes)
  14- 15  I2    s       RA.s    Right ascension 1750 (seconds)
  17- 18  I2    deg     DE.d    Declination south 1750 (degrees)
  20- 21  I2    arcmin  DE.m    Declination south 1750 (minutes)
  23- 24  I2    arcsec  DE.s    Declination south 1750 (seconds)
--------------------------------------------------------------------------------

Byte-by-byte Description of file: lac_ident.dat
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   Bytes Format Units   Label   Explanations
--------------------------------------------------------------------------------
   1-  4  I4    ---     CA      [1-1942]? Catalog number in [CA] (1)
       5  A1    ---   f_EA      [x*]? Issue with observation numbering (2)
   6-  9  I4    ---     EA      [1-1935]? Observation number in [EA]
  11- 16  A6    ---     NA      ?Identifier in [EN] (<class>.<number>)
      17  A1    ---     NoId    [*]? Star if unidentified entry
  18- 24  F7.2  arcmin  dRA     ?Difference in right ascension.cos(DE) (3)
  26- 32  F7.2  arcmin  dDE     ?Difference in declination (3)
  34- 39  F6.2  arcmin  dist    ?Distance between match and Lacaille (3)
  41- 43  A3    ---     BCon    ?Bayer constellation
  45- 47  A3    ---     BLet    ?Bayer letter
      49  A1    ---     BInd    ?Bayer index
  51- 53  A3    ---     FCon    ?Flamsteed constellation
  55- 57  I3    ---     FNum    [1-141]? Flamsteed number
  59- 62  I4    ---     HR      [1-9110]? Bright Star catalog number
  64- 69  I6    ---     HD      [1-359083]? Henry Draper catalog number
  71- 76  I6    ---     HIP     [1-120416]? Hipparcos catalog number
  78- 81  A4    ---     Com     ?Component letter(s) (4)
  83-111  A29   ---     Name    ?Object name(s)
--------------------------------------------------------------------------------

Note (1): the number is missing on lines containing additional matches for the
    current star.

Note (2): an 'x' here marks places where the observation numbers are out of
    sequence, because the reduction of coordinates has caused a change in the
    right ascension order. A '*' here marks entries in Lacaille's catalog that
    don't have a corresponding entry in the observations catalog (there are 7
    of them).

Note (3): difference (HIP - Lacaille), or (HD - Lacaille) if there is no HIP
    match.

Note (4): component letter(s) from the Hipparcos or CCDM catalog.

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References:

[EA] M. l'Abbé de la Caille,
     Table des Ascensions Droites et des Déclinaisons Apparentes des Étoiles
     australes renfermées dans le tropique du Capricorne : observées au cap de
     Bonne-espérance, dans l'intervalle du 6 Août 1751, au 18 Juillet 1752.
     Histoire de l'Académie royale des sciences, Année 1752, pp. 539--592.
     Imprimerie royale, Paris, 1756.

[EN] M. l'Abbé de la Caille,
     Sur les Étoiles Nébuleuses du Ciel Austral.
     Histoire de l'Académie royale des sciences, Année 1755, pp. 194--199.
     Imprimerie royale, Paris, 1761.

[CA] Nicolas-Louis de la Caille,
     Coelum Australe Stelliferum seu Observationes ad Construendum Stellarum
     Australium Catalogum institutae, in Africa ad Caput Bonae-Spei.
     Guerin & Delatour, Paris, 1763.

History:

  * 2018-08-01: initial release.
  * 2018-08-23: correct a few transcription errors in obs_data.dat.
  * 2019-06-09: update lac_ident.dat, merge remove neb_ident.dat into
    lac_ident.dat, merge neb_descr.dat into neb_data.dat, some fixes in
    lac_bids.dat.

================================================================================
