Radiometric validation of the Midcourse Space Experiment's (MSX) Point Source Catalogs and the MSX properties of normal stars

We describe our methods to validate the absolute calibration of the infrare d (IR) radiometry of the Midcourse Space Experiment (MSX) Point Source Cata log, version 1.2 (PSC1.2). These are based upon stars drawn from our curren t all-sky network of absolute calibrators and upon other stars that also su pport the calibration of ESA's Infrared Space Observatory and of several ot her satellites. Based on the mean ratios of (observed/predicted) irradiance s for this ensemble of stars, all four of MSX's mid-IR bands are consistent with this network; i.e., there are no mean ratios that deviate more than 3 sigma from unity. However, the two narrowest bands (near 4.3 mum) are sign ificantly discrepant by a few percent. This paper probes the radiometry of stars fainter than those validated by an independent study of the primary a nd secondary MSX standards by Cohen et al. To provide the user of the PSC1. 2 with a basis for comparison, we derive the IR properties of normal stars from measurements by MSX's IR focal planes.