ENThe manuscript of Supraśl monastery has been studied since the nineteenth century. It consists of different texts but the main attention in historiography is paid to The Secret of Secrets, while astrological texts have not beem analysed deeply. The article is devoted to astrological knowledge about the luminaries and planets contained in the manuscript. There are eighteen astrological texts in it. It can be claimed that all of them, when put together, form a basic astrological textbook. Three special texts describe the Sun, Moon, and five planets. They include information about their cycles, colours, and other characteristic features. Most of the texts came from Byzantium and they were translated from Greek in the second half of the fifteenth century. These translations influenced greatly the culture of the Grand Duchy of Lithuania.