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The UCAC CCD has significant CTE problems, which they correct for astrometry but which undoubtedly contribute to photometric errors. They use a Gaussian fit to the image profile rather than aperture photometry, though they attempt to do an empirical magnitude-dependent correction. The UCAC1 paper (Zacharias, et al. 2000, AJ 120, 2131) indicates that no flatfielding was applied for UCAC1. Combine this with the narrow bandpass, different from either V or Rc, and the fact that fainter stars are systematically redder, and I could believe photometric deviations from some V or Rc catalog both at the faint end and with position on the CCD. Again, UCAC is *not* a photometric catalog. Please don't make it something that it isn't, and don't complain. Others, such as TASS and ASAS, will contribute the photometric part of the picture. Arne
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