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We present photometry for globular and open cluster stars observed with theSloan Digital Sky Survey (SDSS). In order to exploit over 100 million stellarobjects with r < 22.5 mag observed by SDSS, we need to understand thecharacteristics of stars in the SDSS ugriz filters. While star clusters provideimportant calibration samples for stellar colors, the regions close to globularclusters, where the fraction of field stars is smallest, are too crowded forthe standard SDSS photometric pipeline to process. To complement the SDSSimaging survey, we reduce the SDSS imaging data for crowded cluster fieldsusing the DAOPHOT/ALLFRAME suite of programs and present photometry for 17globular clusters and 3 open clusters in a SDSS value-added catalog. Ourphotometry and cluster fiducial sequences are on the native SDSS 2.5-meterugriz photometric system, and the fiducial sequences can be directly applied tothe SDSS photometry without relying upon any transformations. Model photometryfor red giant branch and main-sequence stars obtained by Girardi et al. cannotbe matched simultaneously to fiducial sequences; their colors differ by~0.02-0.05 mag. Good agreement (< ~0.02 mag in colors) is found with Clem etal. empirical fiducial sequences in u'g'r'i'z' when using the transformationequations in Tucker et al.

Galactic Globular and Open Clusters in the Sloan Digital Sky Survey. I. Crowded Field Photometry and Cluster Fiducial Sequences in ugriz