Abstract. CCD observations of field stars in an area north-east of the globular cluster M 56 were obtained in six bands of the Vilnius photometric system. The data sets cover a field of 9. × 9. 5. An outline of the data pathway from observations to reduction via IRAF is outlined in this text. Photometry of 366 stars brighter than 18th V magnitude has been obtained and the analysis of the observational errors is discussed.
Abstract. Three-dimensional classification of stars based on their seven-color CCD photometry in the Vilnius system has been succesfully applied to study the small scale structure of interstellar dust clouds. In the present paper the statistical equations of Münch are modified and applied to stars located beyond the galactic absorbing layer. This particular use of Miinch's statistics and the properties of CCD photometry in the Vilnius system offer a better possibility of probing the small scale structure of interstellar medium outside of the solar vicinity. This new technique and the first results are discussed.
Abstract. CCD observations of the southern clusters NGC 4755 and 47 Tucanae were obtained in the Vilnius photometric system. A brief outline of the data pathway from observations to final analysis via IRAF and ASCAR software is given.
Abstract. Seven-color CCD photometry in the Vilnius photometric system of 279 stars down to V -15 mag in the open cluster M 67 area is obtained. 13 standard stars in the cluster are measured photoelectrically. Photometric spectral types have been determined for all the stars. The reddening of the cluster is found to be EB-V = 0.045, the true distance modulus is 9.38 mag and the age is 4X10 9 years.
Abstract. Seven-color photometry in the Vilnius system has been obtained for 420 stars down to V = 16 mag in the area containing the overlapping open clusters NGC 1750 and NGC 1758 in Taurus. Spectral and luminosity classes, color excesses, interstellar extinctions and distances are given for 287 stars. The classi cation of stars is based on their reddening-free Q-parameters. 18 stars observed photoelectrically were used as standards. The extinction vs. distance diagram exhibits the presence of one dust cloud at a distance of 175 pc which almost coincides with a distance of other dust clouds in the Taurus complex. The clusters NGC 1750 and NGC 1758 are found to be at the same distance of 760 pcand may penetrate each other. Their interstellar extinction A V is 1.06 mag which corresponds to E B;V = 0.34 mag. (1992, hereafter Paper I). Photoelectric photometry of 116 stars down to 13th magnitude has revealed that the clusters are at 510 and 680 pc distances, respectively. Interstellar reddeningE B;V of both clusters was found to beclose to 0.4 mag. The distance of the dust layer responsible for the reddening was found to be at 175 pc. The reality of the clusters was veri ed by their photometric distances and proper motions of the cluster members.Paper I has increased the interest in this pair of clusters. In a series of papers Galadi-Enriquez et al. (1998a,b,c) have con rmed the reality of the two clusters. Their investigation was based on stellar photometry in the UBVRI photometric system by CCD and photographic techniques down to 18{20 mag and on the proper motions of stars based on a plate collection covering a broad range of epochs (from 1891 to 1994). The lists of NGC 1750 and NGC 1758 members down to V = 15 mag were composed containing 79 and 57 stars respectively. For bothclusters the reddening E B;V = 0.34 mag, based on the member stars measured by Strai zys et al. (1992) in the Vilnius system and by the authors in the Str omgren system. The distances to the clusters were found to be630 pc and 760 pc. Another proper motion study in the area was published by Tian et al. (1998).Trying to obtain an independent criterion of membership to both clusters, based on photometric classi cation of stars in terms of MK spectral and luminosity classes, we have started a new investigation of the cluster area in the Vilnius system by CCD photometry, extending photometric classi cation down to a fainter limit in comparison to Paper I. Although the preliminary results of the present study were known already in 1995{1996, the publication was delayed due to problems of at-elding and CCD non-linearity.
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