The globular cluster NGC 1904 (M 79, 
, 
, 1950.0; 
, 
) belongs to
comparatively well-studied Milky Way globulars. It was photometrically
studied several times during the recent two decades, after the first
studies by Goranskij (1976) and Alcaíno (1976). The list of
corresponding papers may be found in Alcaíno et al. (1994). The latter
paper contains the results of the deepest multicolor (BVRI) CCD
photometry and of its isochrone analysis. Comparison is made with
photometric data by other authors who reduced observations of M 79
using different reduction software, among them, with most extensive
CCD BV photometry by Ferraro et al. (1992). The photometry of
Ferraro et al. covers a wide field in M 79; they obtained and
analysed a deep V-(B-V) diagram, also well represented in the region
of red giant branch (RGB) and horizontal branch (HB) stars.
This paper continues the deep photometric studies of M 79. Our observations were obtained for calibration purposes in the frame of our study of NGC 1841 (Alcaíno et al. 1996), but, thanks to the large telescope and high-quality, wide-format CCD detector used under excellent seeing, the results deserve special evaluation. We have achieved improved photometric accuracy, especially around the main-sequence turnoff point, along the subgiant branch and lower RGB, with a reasonably rich sample of stars belonging to the upper main sequence. Moreover, we have been able, for the first time, to add sufficiently deep U photometry.