Optical Counterparts of Ultraluminous X-Ray Sources NGC 4559 X-10 and NGC 4395 ULX-1 of ultraluminous
X-ray sources (ULXs) NGC 4559
X-10 and NGC 4395 ULX-1. Their absolute magnitudes, after taking
X-ray testing of the multifoil optical system REX II for rocket experiment). This optical device is based on successful mission REX1. The purpose of REX2 is to verify
X-ray optical system