Volume 45 number 1 (2017)
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Four observers, over a wide geographic range, observe slowly-varying stars in Johnson B and V bands using Optec SSP-3 and SSP-5 photometers on telescopes of modest size. Significant corrections for transformation and extinction were applied to their data, and we find very close agreement among them. In paired same-night observations, the median absolute difference between observers was 7 mmag. For the two observers with the most measurements in common, we estimate a systematic difference of 3.2 mmag or less.