ИСТИНА

The primary cosmic ray research method using EAS Cherenkov light reflected from snow is implemented at SINP Lomonosov Moscow State University. It was successfully used to measure the spectrum and chemical composition of primary cosmic rays in 2011-2013. A new airborne Cherenkov telescope SPHERE-3 is under development. It will be carried by an unmanned aerial vehicle and will detect both reflected and direct Cherenkov light from extensive air showers. Calculations are carried out to determine the optimal telescope design for better mass separation of cosmic rays. Recent results for the new telescope are presented.