1994PASP..106..726S

Van den Bergh (1993, ApJ, 411, 178) has argued that NGC 6287 = C1702-226 may be the oldest globular cluster in the Galaxy, but apparently there has been no color-magnitude diagram yet published for this heavily reddened, metal-poor system. Here we present a first (B,V) color-magnitude diagram based upon observations obtained in July 1993 with the Jacobus Kapteyn 1m telescope on La Palma. The main-sequence turnoff is not reliably detected, but the cluster is shown to have a strong blue horizontal branch. However, this horizontal branch appears to be peculiar, in the sense that it lies well below and to the red of M15's blue horizontal branch when the two clusters' giant branches are aligned. A reddening value of E_B-V ∼ 0.65 and a true distance modulus in the range (m-M)_0 = 14.1 - 14.4 are crudely estimated from the comparison with M15; an independent argument suggests that the cluster probably lies on the near side of the Galactic bulge. Four candidate RR Lyrae stars and three other possible variable stars are identified, but their membership status is not certain.