1996PASP..108..877J

We discuss a technique to compute using templates developed by fitting a Fourier series to existing high-quality K light curves of field RR Lyraes. We find that a series of order 2 is sufficient to model the light curves of first-overtone RRc variables, but 4 different 6th-order templates are needed for the fundamental RRab stars due to changes in the light curves that appear to correlate with the B amplitude. Applying the appropriate template to single-phase observations yield estimated values whose deviation from the true is randomly distributed over phase, and is of the same order of magnitude as the observational uncertainty, as long as the ephemeris phase is accurate. The addition of a second point, separated by at least 0.2 in phase from the first, allows the use of template-shifting to remove deviations that may arise from uncertainties in the ephemeris phase, and template and scaling factor selection, with final systematic errors reduced to less than 0.03 mag. We find that the use of templates yield superior results to those derived using other techniques, which can produce values that show systematic deviations over phase.