Essaouira was founded n 1764 by Sultan Sidi Muhammad b. Abdullah as his port for developing trade with Europe. Through a group of Jewish middlemen, it served as a link between Europe, Morocco and su-Saharan Africa.  Meer

This book provides a unified treatment of the characteristics of telescopes of all types, both those whose performance is set by geometrical aberrations and the effect of the atmosphere, and those diffraction-limited telescopes designed for observations from above the atmosphere.  Meer