We present in this work secondary catalogs Tables B.1 to B.12 are also available in eletronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr ( 130.79.128.5 ) or via http : //cdsweb.u-strasbg.fr/Abstract.html up to m _ { Val } \sim 13 based on the Tycho reference frame ( ESA , 1997 ) for 12 selected low-extinction fields towards the galactic bulge .
The observations have been performed with the Askania-Zeiss Meridian Circle equiped with a CCD camera , located at the Abrahão de Moraes Observatory ( Valinhos , Brazil ) and operated by the Institute of Astronomy and Geophysics , São Paulo University .
The presented catalog , though not complete , has been designed to help in intensive search programmes ( e.g .
microlensing and variable searches ) and therefore the selected standards have a high astrometric and photometric ( V band , approximately ) quality .
The mean precisions obtained were 0.0018 ^ { s } in \alpha , 0.013 ” in \delta , 0.030 for the standard deviation in magnitude and 0.0042 for the magnitude when weighted with the error bars in each night ( in the mean , 42 stars for the catalog of each window ) .