HD 185691

Longterm Photometry of Variables at ESO - Part Two - the Second Data Catalogue 1986-1990 Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993A&AS..102...79S&db_key=AST
Long-term photometry of variables at ESO. I - The first data catalogue (1982-1986) This paper presents the catalog of photometric data in the Stromgrensystem obtained during the first four years (October 1982 - September1986) of the Long-Term Photometry of Variables (LTPV) program at ESO.The data are available in computer-readable form.
Instrumental effects and the Stroemgren photometric system The extent to which the use of different photometers can affect resultson stellar color indices was investigated by simultaneously observing asample of widely different stars with several uvby photometric systemsavailable at the ESO, La Silla, Chile. In one instance, the ESO 50-cmtelescope and the four-channel photometer at the Danish 50-cm telescopewere used simultaneously. The reductions were performed separately oneach data set, using a linear color transformation procedure. Theresults agree with theoretical investigations which showed thatsubstantial errors can arise from the nonconformity of passbands. It isemphasized that it is necessary to use separate color transformationsfor various stellar types and classes and for different interstellarreddenings.

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