DIVISION IX / COMMISSION 25 / WORKING GROUP INFRARED ASTRONOMY

As we have noted before, the WG-IR was created following a Joint Commission Meeting at the IAU General Assembly in Baltimore in 1988, a meeting that provided both diagnosis and prescription for the perceived ailments of infrared photometry at the time. The results were summarized in Milone (1989). The challenges involve how to explain the failure to systematically achieve the milli-magnitude precision expected of infrared photometry and an apparent 3% limit on system transformability. The proposed solution was to re-define the broadband Johnson system, the passbands of which had proven so unsatisfactory that over time effectively different systems proliferated although bearing the same JHKLMNQ designations; the new system needed to be better positioned and centered in the atmospheric windows of the Earth's atmosphere, and the variable water vapour content of the atmosphere needed to be measured in real time to better correct for atmospheric extinction.