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Precision uvbyCa Hbeta photometry of the metal-deficient, old open cluster,NGC 2506, is presented. The survey covers an area 20 by 20 arcminutes, andextends to V~18 for b-y and Hbeta and to V~17.0 for c_1 and hk. For V < 16.0,photometric scatter among the indices leads to the recovery of 6 knownvariables within the cluster core and 5 new variables in the outer 5 arcmin ofthe survey field. Proper motions, radial velocities, and precise multicolorindices are used to isolate a highly probable sample of cluster members fromthe very rich color-magnitude diagram (CMD). From 257 highly probable membersat the cluster turnoff, we derive a reddening estimate of E(b-y) = 0.042 +/-0.001 (E(B-V) = 0.058 +/- 0.001), where the errors refer to the internalstandard errors of the mean. [Fe/H] is derived from the A/F dwarf members usingboth m_1 and hk, leading to [Fe/H] = -0.296 +/- 0.011 (sem) and -0.317 +/-0.004 (sem), respectively. The weighted average, heavily dominated by hk, is[Fe/H] = -0.316 +/- 0.033. Based upon red giant members, we place an upperlimit of +/- 0.010 on the variation in the reddening across the face of thecluster. We also identify two dozen potential red giant cluster members outsidethe cluster core. Victoria-Regina isochrones on the Stromgren system produce anexcellent match to the cluster for an apparent modulus of (m-M) = 12.75 +/- 0.1and an age of 1.85 +/- 0.05 Gyr.

WIYN Open Cluster Study. LXXII. A uvbyCa Hbeta CCD Analysis of the Metal-Deficient Open Cluster, NGC 2506