not only did he convince them, uncle, general hallmarkco, or hello con, to spare his life, he convinced him to build him a new observatory in return altos, who promised to provide the general with his astrological chart, so that he'd know what day to go to battle. the more of the observatory became the most important of its day, and a great hub international find to collaboration. ah, of course, was great about the morale, the observatory in astronomy. there isn't the observations they may, they didn't have telescopes, but it's the mathematical tricks they develop. that will be influential in astronomy, for centuries to come. and i wanted to show you something here. so this is a diagram for me to seize work. people like to see when they're looking at trying to explain how the stars and planets moved. they were trying to develop the math to make it sensible. you know, they were using the greek model. yeah. which had gone incredibly complicated course . the greeks believed the central solar system in order to make the mathematical model fit the observations of the way in which the planets