Atmospheric extinction and its removal in the Vilnius photometric system

Section: Observations Reductions and The Catalogmentioning

confidence: 99%

Photometric Investigation Of The California Nebula Region: Catalogs

Straižys¹,

Cernis²,

Bartasiute³

2001

“…Also, a depends on the energy distribution in the spectrum. Synthetic photometry was used to calculate the theoretical extinction coefficients for the UBV system by Azusienis & Straizys (1966b, 1969b and Zdanavicius (1975), for the Vilnius system by Zdanavicius (1970Zdanavicius ( , 1975, for the uvby system by Tautvaisiené & Straizys (1985). For color indices, containing a broad-band ultraviolet passband, the dependence of a on spectral class, luminosity and interstellar reddening is quite complicated (Fig.…”

Section: Reduction To Outside the Atmospherementioning

confidence: 99%

The method of synthetic photometry

Straižys¹

1996

Abstract. The method of synthetic photometry, using the calculation of magnitudes, color indices and other photometric quantities of stars from their spectral energy distribution functions, is being used for obtaining the transformation relations between various photometric systems, the selection of optimum positions of passbands for stellar classification, for investigation of interstellar and atmospheric extinction effects (the band-width effect), for restoration of response functions of the photometric system, for calibrations of photometric quantities in terms of physical parameters of stars, for calibration of magnitudes in absolute fluxes and many other tasks. The paper describes the history of the method and its different applications.

“…All the observations were tied into the standard Vilnius system given by Straizys (1992), using transformation equations determined by a series of observations of the Cygnus Region standards (Zdanavicius & Cerniene (1985) details of the data reduction procedures, see Bartasiute 1999.) The internal standard errors in V and color indices were found to be below 0.010 mag for a single observation.…”

Section: Observationsmentioning

confidence: 99%

Photoelectric Vilnius photometry of Hipparcos turn-off region stars

Bartasiute¹,

Ezhkova²,

Lazauskaite³

1999

Abstract. Seven-color photometry in the Vilnius system and photometric classification in terms of spectral type, absolute magnitude and metallicity are presented for 145 Hipparcos stars of the turn-off region, most of which have parallaxes determined to an accuracy of at least 15%. The stars selected for the observing program included those identified kinematically as intermediate between the thin disk and halo, plus a number of weak-lined stars discovered previously from objective prism surveys. The metallicity distribution we find for a kinematically defined sample of possible members of the thick disk has a mean abundance [Fe/H]=-0.3 dex and a dispersion of 0.3 dex. Our data seem to suggest a large age for this intermediate population.