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Description
We present BVRI photometry of the low metallicity globular cluster M68 (NGC 4590) observed with a CCD camera and the 2.2m telescope at ESO/La Silla, and have compared our BV color-magnitude diagrams with the observational results of a previous research. At magnitudes V<22, our BV results, obtained using the INVENTORY code, are in very close agreement with those of the other authors who used DAOPHOT in their reductions. At fainter levels, selection effects appear to affect INVENTORY more than DAOPHOT. We find that V_TO-HB_=3.42+/-0.10, in accord with values found for other clusters. The comparison between our four-color observations and the theoretical isochrones consistently yield a cluster age of 13Gyr with a likely external uncertainty of 2 or 3Gyr. Our derived values for the interstellar reddening at longer wavelengths are generally in agreement (+/-0.02mag) with what would be expected assuming E(B-V)=0.07mag and (m-M)_V_=15.25.
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