Asteroid observations at low phase angles. Average parameters for the new three-parameter H,G1,G2 magnitude system

Asteroid observations at low phase angles. Average parameters for the new three-parameter H,G1,G2 magnitude system V. Shevchenko1, I. Belskaya1, K. Muinonen2, Y. Krugly1, F. Velichko1, V. Chiorny1, I. Slyusarev1, N. Gaftonyuk3, and I. Tereschenko1 1Institute of Astronomy of Kharkiv Karazin National University, Kharkiv 61022, Sumska str. 35, Ukraine 2Department of Physics, Gustaf Hallstromin katu 2a, P.O. Box 64, FI-00014 University of Helsinki, Finland 3Crimean Astrophysical Observatory, Crimea, Simeiz 98680, Ukraine