The BV photographic photometry was made for 1714 stars (V < 19.5m) in NGC 6752, using 83 photoelectric stars and many secondary photographic standard stars over the area of 3.3' - 11.3' from the cluster center. Their data and finding chart are presented.
More than 22,300 stars in NGC 6752 were measured over the region of 5' < r < 23' in B and V AAT plates. The most of these are main sequence(MS) stars and about 130 blue horizontal branch(BHB) stars were detected. The C-M diagram of all measured stars shows gaps appearing at V≈15.m2 and 16.m2 along the red giant branch(RGB) and their appearance shown by Lee & Cannon(1980) is found to be independent of measured region. The bimodal distribution of BHB stars is confirmed again and a wide gap shown by Lee & Cannon(1980) at V≈16m is clearly seen for stars in the outer part (8' < r < 13') in the cluster. It is noted, however, that this gap is occupied by about a dozen of BHB staIs located in the inner region (5' < r < 8'). The number ratio of bright BHB star (V < 15m) to faint BHB stars (V > 15m) decreases with increasing radial distance from the cluster center. Three faintest BHB stars were found, and two stars (V≈18.m5) of there are located in the inner region of r≈6' and the other faintest one (V≈19.m3) located in the outer part of r≈13'. Also a bluest star of (B - V) ≈ -0.5 at V≈17.m2 is found but it is located at the outer part of r≈13' in NE region. Therefore, the membership of the faintest BHB star and bluest star is suspected. The luminosity function(LF) and mass function(MF) for NGC 6752 were derived for MS stars. The LF for stars of Mv< 6m in the outer part of r > 8' shows a consistency with that derived by Penny & Dickens(1986).
The BV-photographic photometry was made for 1714 stars (V<19.5) in NGC 6752. The C-M diagram of this cluster shows an unusually extended blue horizontal branch ( V = 13.5 ∼ 17.8 ) with a wide gap ( V = 16 ∼ 16.7 ) and the well defined giant branch with gaps at V=13.85 and 16.2. The turnoff point is defined at V = 17.25 ± 0.15 and (B-V) = 0.46 ± 0.02 . If we take V H B = 13.85 for NGC 6752, then Δ V = 2.80 , ( B − V ) 0 , g = 0.76 a n d Δ V T O = 3.40 and the chemical abundance is estimated to be [Fe/H]=-1.67 or Z = 4.3 × 10 − 4 a n d Y = 0.26 . Some other physical parameters of this cluster are derived and compared with those for the well observed clusters M 3, M 13, M 15 and M 92.