Access to Astronomical Catalogues

J/A+A/548/A16       Improved astrometry bor BE74 stars         (Howarth, 2012)
Improved astrometry for the Bohannan & Epps catalogue.
    Howarth I.D.
   <Astron. Astrophys. 548, A16 (2012)>
   =2012A&A...548A..16H
ADC_Keywords: Positional data ; Cross identifications ; Stars, emission

Keywords: astrometry - stars: emission-line - Magellanic Clouds


Abstract:
    Accurate astrometry is required to reliably cross-match 20th-century
    catalogues against 21st-century surveys. The present work aims to
    provide such astrometry for the 625 entries of the Bohannan & Epps
    (BE74; 1974A&AS...18...47B) catalogue of Hα emission-line stars.
    BE74 targets have been individually identified in digital images and,
    in most cases, unambiguously matched to entries in the UCAC4 (I/322)
    astrometric catalogue.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table1.dat       165      647  *Astrometry for BE74 targets (corrected for small
                              zero-point offsets as described in the text)
table2.dat        80      116   Notes on individual objects
table3.dat        65      202   Positional matches between measured BE74
                              co-ordinates and Skiff's results for HDE, Sk,
                              and LHA 120-S targets, within a 5 arcsec radius

Note on  table1.dat: Remaining data are representative measurements from UCAC4
  (via CDS/Vizier, Cat. I/322). Where available, the UCAC4 astrometry is to be
  preferred. Note that additional information is available in UCAC4, including
  proper motions, which are generally negligible for the BE74 sources.


See also:
   I/322 : UCAC4 Catalogue (Zacharias+, 2012)


Byte-by-byte Description of file: table1.dat

   Bytes Format Units   Label     Explanations

   1-  3  I3    ---     [BE74]    Sequential number
       4  A1    ---     m_[BE74]  Multiplicity index on [BE74]
                                   (? when no positions measured)
   8-  9  I2    h       RAh       ? Measured right ascension (J2000)
  11- 12  I2    min     RAm       ? Measured right ascension (J2000)
  14- 18  F5.2  s       RAs       ? Measured right ascension (J2000)
      21  A1    ---     DE-       ? Measured declination sign (J2000)
  22- 23  I2    deg     DEd       ? Measured declination (J2000)
  25- 26  I2    arcmin  DEm       ? Measured declination (J2000)
  28- 31  F4.1  arcsec  DEs       ? Measured declination (J2000)
  37- 38  I2    h       RA4h      ? Matching UCAC4 right ascension (J2000)
  40- 41  I2    min     RA4m      ? Matching UCAC4 right ascension (J2000)
  43- 48  F6.3  s       RA4s      ? Matching UCAC4 right ascension (J2000)
      50  A1    ---     DE4-      ? Matching UCAC4 declination sign (J2000)
  51- 52  I2    deg     DE4d      ? Matching UCAC4 declination (J2000)
  54- 55  I2    arcmin  DE4m      ? Matching UCAC4 declination (J2000)
  57- 61  F5.2  arcsec  DE4s      ? Matching UCAC4 declination (J2000)
  67- 76  A10   ---     UCAC4     UCAC4 designation (ZZZ-NNNNNN)
  80- 82  I3    mag     ePos      ? Total mean error on position at Ep=J2000 (3)
  84- 89  F6.3  mag     f.mag     ? UCAC4 fit model magnitude (579-642nm) (4)
      91  I1    ---     of        [0/9]? UCAC4 object classification flag (6)
  93- 94  I2    ---     db        [0/36]? UCAC4 double star flag (7)
  99-104  F6.3  mag     Jmag      ? 2MASS J magnitude
 106-111  F6.3  mag     Kmag      ? 2MASS Ks magnitude
 113-118  F6.3  mag     Bmag      ? B magnitude from APASS (12)
 120-125  F6.3  mag     Vmag      ? V magnitude from APASS (12)
 127-132  F6.3  mag     rmag      ? r magnitude from APASS (12)
     134  I1    ---     H         [0/9]? Hipparcos/Tycho flag (15)
 136-165  A30   ---     Note      Note

Note (3): taking into account the propagation of the proper motion error
     between the mean epoch and J2000.
Note (4):  systematic errors are expected to be below 0.1mag.

Note (6): the object type flag is used to identify possible problems with a star
     and has the following meaning:
  0 = good, clean star, no known problem
  1 = near overexposed star
  2 = possible streak object
  3 = high proper motion (HPM) star
  4 = actually use external HPM data instead of UCAC4 observed data
      (accuracy of positions varies between catalogs)
  5 = poor proper motion solution, report only CCD epoch position
  6 = substitute poor astrometric results by FK6/Hip/Tycho-2 data
  7 = added supplement star (no CCD data) from FK6/Hip/Tycho-2 data,
      and 2 stars added from high proper motion surveys
  8 = high proper motion solution in UCAC4, star not matched with PPMXL
  9 = high proper motion solution in UCAC4, discrepant motion to PPMXL
Note (7):  The double star flag is used to indicate the type/quality
      of double star fit. It is a combination of 2 flags, dsf+dst:
   * dsf = double star flag, represents the overall classification:
       0 = single star
      10 = component #1 of "good" double star
      20 = component #2 of "good" double star
      30 = blended image
   * dst = double star type, derived from pixel data image profile fits
           (largest value of all images used for this star):
       0 = no double star, not sufficient #pixels or elongation
           to even call double star fit subroutine
       1 = elongated image but no more than 1 peak detected
       2 = 2 separate peaks detected -> try double star fit
       3 = secondary peak found on each side of primary
       4 = case 1 after successful double fit (small separation, blended image)
       5 = case 2 after successful double fit (most likely real double)
       6 = case 3 after successful double fit (brighter secondary picked)
Note (12):  Data are from the AAVSO Photometric all-sky survey (APASS) DR6
     plus single observation stars kindly provided by A.Henden. For bright
     stars the Bmag and Vmag columns contain the Hipparcos/Tycho Bt and Vt
     mags respectively, whenever there is no APASS B or V available and
     valid Bt or Vt mags were found. The errors flagged with "-" are formal
     errors estimated from the S/N, while the "normal" errors (flagged with
     ".") are from the official release data error estimates (at least 2
     observations per star).
Note (15): The FK6-Hipparcos-Tycho-source-flag has the following meaning:
   0 = not a Hipparcos or Tycho star
   1 = Hipparcos 1997 version main catalog (Cat I/239)
   2 = Hipparcos double star annex
   3 = Tycho-2 (Cat. I/259)
   4 = Tycho annex 1
   5 = Tycho annex 2
   6 = FK6 position and proper motion (instead of Hipparcos data)
   7 = Hippparcos 2007 solution position and proper motion (Cat. I/311)
   8 = FK6, only PM substitution (not in UCAC4 data)
   9 = Hipparcos 2007, only proper motion substituted (Cat. I/311)


Byte-by-byte Description of file: table2.dat

   Bytes Format Units   Label     Explanations

   1-  3  I3    ---     [BE74]    Sequential number
   6- 80  A75   ---     Notes     Notes (1)

Note (1): acronyms used:
 * 'BE74' refers to Bohannan & Epps 1974A&AS...18...47B;
 * 'HW' to charts from the Hodge & Wright Atlas (Hodge & Wright 1967, 
   The Large Magellanic Clous (Smithsonian Press, Washington D.C.);
 * 'RPs' to emission-line stars catalogued by Reid & Parker
   (2012MNRAS.425..355R, RP12) and
 * 'DSS2' to the red Digital Sky Survey images accessed through Aladin.
 * 'A','B' etc. refers to separate entries in Table 1.


Byte-by-byte Description of file: table3.dat

   Bytes Format Units   Label     Explanations

   1-  3  I3    ---     [BE74]    BE74 number (use in conjunction with Table 1)
       4  A1    ---     n_[BE74]  Multiplicity index on [BE74]
   8- 16  A9    ---     HDE       HDE match
  19- 22  F4.2  arcsec  offHDE    ? HDE match offset
  27- 36  A10   ---     Sk        Sk match
  38- 41  F4.2  arcsec  offSk     ? Sk match offset
  46- 58  A13   ---     LHA       LHA12-S match
  62- 65  F4.2  arcsec  offLHA    ? LHA12-S match offset


Acknowledgements:
   Ian Howarth, idh(at)star.ucl.ac.uk
(End)                                     Francois Ochsenbein [CDS]  05-Oct-2012