BALLOON- AND SATELLITE-MOUNTED LIGHT SOURCES AS PHOTOMETRIC CALIBRATION STANDARDS FOR GROUND-BASED TELESCOPES

Significant and growing portions of systematic error on a number of fundamental parameters in astrophysics and cosmology, especially those related to dark energy, are due to uncertainties from absolute photometric and flux standards. A path toward achieving major reduction in such uncertainties may be provided by well-calibrated light sources above the atmosphere, resulting in improvement in the ability to precisely characterize the magnitude scale and atmospheric extinction, and thus helping to usher in the coming generation of precision results in cosmology. Future instrumentation is briefly outlined. Subject headings: balloons, instrumentation: photometers, cosmology: large-scale structure of universe