Infrared photometry of Magellanic Cloud Cepheids: observations and error analysis.

JHK photometry, obtained during 1982, 1983, and 1984, for 21 Cepheids in Large Magellanic Clouds is examined. Complete phase coverage for the Cepheids is obtained and used to derive the mean magnitudes and colors. These data are then employed to obtain distance measurements. Tables of LMC and SMC, and light curves are presented; the accuracy of the observations is evaluated. Potential errors in the mean magnitudes and colors are analyzed. The light curves are studied in order to determine the amplitudes and phases of pulsations. It is observed that the mean dereddened magnitudes are at 0.010-0.020 m and the color indices at 0.010-0.016 m with a low systematic error of 0.01 + or - 0.01.