After 1998 the UKIRT cameras were equipped with the the better-defined "Mauna Kea" JHK filter set now being adopted by many major observatories (see "The Mauna Kea Observatories Near-Infrared Filter Set. I. Defining Optimal 1-5 Micron Bandpasses" by Simons & Tokunaga 2002 PASP 114, 169 and "The Mauna Kea Observatories Near-Infrared Filter Set. II. Specifications for a New JHKL'M' Filter Set for Infrared Astronomy" by Tokunaga et al. 2002 PASP, 114, 180). Initially we derived colour transformation between the old UKIRT system and the new system defined by the MK set, and the results are given below.

In 2001 we started reobserving all the standards through the MK filter set to directly determine the magnitudes on the new system. The results are given at the link below - these values should be used instead of the transformed values. (We also observed the KPNO standards (Persson et al. 1998, AJ 116, 2475) through the MKO filter set. Preliminary results are given in the combined IZYJHKL'M' data text file.)