Acta Astronomica Archive

Data related to the paper by Michalska et al. 
"A CCD Search for Variable Stars of Spectral Type B in the Northern Hemisphere Open Clusters. VII. NGC 1502"
The data consist of:
- Table 4 in the electronic form (Table4.txt)
- Light curves of 11 variables (NGC1502_LC.tar.gz archive, 44 files)
- Description of their contents (this file, ReadMe)


Table4.txt: UBVI_C and Halpha photometry and coordinates of stars in the field of NGC 1502.
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The consecutive columns contain:
  1: Star number according to the WEBDA database.
  2: Right ascension of a star, epoch 2000.0 (in h, min, and seconds).
  3: Declination of a star, epoch 2000.0 (in degrees, arcmin, arcsec).
  4: V magnitude.
  5: Error of V magnitude (see Note 1).
  6: Error of V magnitude, transformation errors included (see Note 1).
  7: V-Ic color index.
  8: Error of (V-Ic), see Note 1.
  9: Error of (V-Ic), transformation errors included (see Note 1).
 10: B-V color index.
 11: Error of (B-V), see Note 1.
 12: Error of (B-V), transformation errors included (see Note 1).
 13: U-B color index.
 14: Error of (U-B), see Note 1.
 15: Error of (U-B), transformation errors included (see Note 1).
 16: Alpha index.
 17: Error of alpha index.
 18: Identification according to Zug (1933, Lick Obs. Bull. 16,119).
 19: Identification according to Purgathofer (1964, Ann. Univ. Sternw. Wien 26, No.2).
 20: Identification according to Hoag et al. (1961, Publ. USNO, Second Ser. 17, 345), photoelectric sequence.
 21: Identification according to Hoag et al. (1961, Publ. USNO, Second Ser. 17, 345), photographic sequence.
 22: Identification according to Dombrovskii & Hagen-Thorn (1964, Publ. Astron. Obs. Univ. Leningrad 20, 75).
 23: Identification according to Tapia et al. (1991, MNRAS 253, 649).
 24: Notes.

Note 1: We provide two different estimates of errors. The first one is calculated as an r.m.s. error of a mean of differential
  magnitudes and does not include the errors of the transformation to the standard system.  Because differential magnitudes 
  were calculated with W30 as a comparion star, this error for W30 equals to zero. Note that these errors show the internal 
  precision of our photometry.  The other error includes the errors of the transformation coefficients.



Light curves of variable stars.
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The light curves for variable stars are archived in the NGC1502_LC.tar.gz archive containing 44 files.
The files are named according to the following way: Star-<name_of_a_star>-<filter>-<camera>[-av].dat,
where:
  <name_of_a_star> is the name (number) of variable star (see Table 1 of the paper),
  <filter> is one of the filters we used, i.e., U, B, V or I,
  <camera> stands for `OLD' or `NEW', see paper for the explanation,
  The `-av' means that the data come from the averaged photometry.
For example, Star-23-V-NEW-av.dat file contains differential V-filter photometry for star WEBDA 23 made with the
new camera and averaged. 
The files with the averaged photometry contain 5 columns:
  1: Heliocentric Julian Day,
  2: Differential magnitude,
  3: Error of magnitude (as calculated by Daophot),
  4: Air mass,
  5: Number of averaged data points.
The files for stars with not-averaged photometry have the same format except for the fifth column which is omitted.