UKIRT Faint JHK Standards:

UKIRT Faint JHK Standards:

The UKIRT Faint Standards (Casali & Hawarden, 1992: UKIRT Newsletter, 4, 33) were reobserved with the IRCAM3 imager between 1994 and 1998. This fundamental list was simultaneously used to calibrate an extended list of additional stars. In combination these provide JHK magnitudes and colours, with errors averaging < 0.m005, for 83 stars between -20° and +54° DEC and with a wide range of colours. All are faint enough for observation with 5m-class telescopes and most should be observable with 10m-class telescopes. Links are given below to the IRCAM3 results for the fundamental and extended lists. Full information on each catalogue is provided.

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.)