
%0 Journal Article
%A Sung, Hwankyung 
%A Bessell, Michael S. 
%T Standard stars: CCD photometry, transformations and comparisons
%J Publications of the Astronomical Society of Australia
%D 2001/04/02
%V 17
%N 3
%P 244-254
%K 
%R https://doi.org/10.1071/AS00041
%U https://www.publish.csiro.au/paper/AS00041 
%X We discuss variations of the atmospheric extinction coefficients and transformation equations to the standard UBVRI system based on observations of standard stars during 1996–1997 at Siding Spring Observatory using a thinned SITe CCD and coloured glass filters. In the transformation from the initial natural system to the Landolt version of the standard system, a large nonlinear term related to the Balmer discontinuity was required for the U transformation. We then modified the U filter, and the subsequent transformation to the SAAO version of the standard UBVRI system had only small nonlinear correction terms for U, B, and I. The correction terms relating to U and B are evidently due to the Balmer discontinuity, while that relating to I seems to be due to the Paschen discontinuity at ? ? 8200 Å. We also compared the results with Landolt’s observations, and confirmed the difference between the two sets of standard stars (SAAO and Landolt). 
