Аннотация:The “Lyra” space experiment is currently being prepared in Russia. Its main goal is to perform high precision 10-color photometry for all V<16 mag stars. Observations will be made using a 500-mm diameter 3-m focal length Ritchey-Chretien telescope with an afocal lens corrector mounted on the Russian segment of the International Space Station (ISS) and equipped with CCDs operated in the time delay and integration (drift, TDI) mode. One of the most important tasks of the “Lyra” mission is to create a dense all-sky grid of high-precision photometric standards. The total number of standards should be on the order of several million, and to achieve this goal, more than 300 million stars will be measured in the course of the mission. The photometric system must include standards in all ranges of magnitudes from the brightest stars down to 16th magnitude. Small random error will be achieved by providing sufficiently strong signal in all passbands and using highly accurate and stable detecting equipment. The random error of measured magnitudes is expected to be 0m.001–0m.003 and about 0m.01 for stars brighter than 14th magnitude and fainter stars, respectively. The system must be free from systematic errors, which are to be minimized by careful ground-based calibration and by maintaining this calibration throughout the mission.
