Photometric catalog of nearby globular clusters^*

II. A large homogeneous color-magnitude diagram data-base

¹ Telescopio Nazionale Galileo, vicolo dell'Osservatorio 5, I-35122 Padova, Italy
² Instituto de Astrofisica de Canarias, Via Lactea, E-38200 La Laguna, Tenerife, Spain
³ Dipartimento di Astronomia, Univ. di Padova, vicolo dell'Osservatorio 5, I-35122 Padova, Italy

Send offprint request to: A. Rosenberg, e-mail: alf@ll.iac.es

Received: 24 February 2000
Accepted: 6 June 2000

Abstract

In this paper we present the second and final part of a large and photometrically homogeneous CCD color-magnitude diagram (CMD) data base, comprising 52 nearby Galactic globular clusters (GGC) imaged in the V and I bands.
The catalog has been collected using only two telescopes (one for each hemisphere). The observed clusters represent of the known Galactic globulars with  mag, cover most of the globular cluster metallicity range (), and span Galactocentric distances from to  kpc.
In particular, here we present the CMDs for the 13 GGCs observed in the Northern hemisphere. The remaining 39 Southern hemisphere clusters of the catalog have been presented in a companion paper (Rosenberg et al. 2000). We present the first CCD color magnitude diagram for NGC 6779 (M 56).
All the CMDs extend from at least magnitudes below the turn-off (i.e. ) to the tip of the red giant branch. The calibration has been done using a large number of standard stars, and the absolute calibration is reliable to a  mag level in both filters.
This catalog, because of its homogeneity, is expected to represent a useful data base for the measurement of the main absolute and relative parameters characterizing the CMD of GGCs.