SIMBAD references

A set of standard areas of the Stromvil system is described. Preliminary values of the color indices for standard stars for photoelectric work may be obtained from their published values in both parent (uvby and Vilnius) systems. Stars in 19 open clusters already observed in both systems may be used as preliminary standards. Standard areas for the CCD work are to be measured anew. For this, a set of 12 compact open clusters and globular clusters have been selected, six areas in each hemisphere, mostly at declinations +30 deg and –30 deg. The 10–20 arcmin areas will contain standard stars of 10–16 mag. They will be good for fixing the zero-point of magnitudes and color indices, for the determination of extinction coefficients in the Earth's atmosphere and for the determination of color equations between instrumental CCD systems and the standard Stromvil system. The first observations in this program are planned with the new 1.8-m Vatican telescope on Mt. Graham, Arizona.