Lecture notes with comments to a set of astronomical lanterns slides of the same title. The full title of the lecture is 'A compendium of astronomy: being a concise description of the most interesting phenomena of the heavens intended to accompany a series of thirty diagrams, contained in single sliders, the paintings three inches in diameter exhibited by the improved phantasmagoria lantern'. The slides and the notes were produced by Carpenter & Westley. The lecture explains what is seen in the images that were projected from lantern slides on to a screen. This version is from 1849 but an earlier version from 1837 is also known. Carpenter and Westley's lantern slide set on astronomy was widely used in (popular) education on the subject, and examples of slides can be found in several collections. To learn more about Carpenter and Westley and to see examples of slides in their collection, visit the Lucerna Magic Lantern Web Resource http://slides.uni-trier.de/organisation/index.php?id=1000618 .