ASTR 101 Lecture Notes - Lecture 9: Angular Diameter, Umbral Calculus

• School: Queen's University
• Department: Physics, Engineering Physics and Astronomy
• Course: ASTR 101
• Professor: David Alan Hanes

Document Summary

Lecture 9 - the moon and the planets. Full moon is always directly opposite from the sun. When crest is east of sun, it sets west shortly after sound does. If the crest is west of the sun, it sets west shortly before the sun does. Moon rotates exactly once overtime it goes around earth; called resonance. One side of moon always hidden but not always in darkness; all parts of the moon have alternating light and dark on a one-month timescale. How big an object looks (angular size) depends on the how big it really is and how far away it is. Sun and moon have almost exactly the same angular size. Sun is 400x as big but also 400x farther away; moon can make perfect eclipses; just exactly cover the sun. Moon is actually orbiting further away from the earth; we"re living in the perfect time to see eclipses. Longest possible period of totality is about 7 minutes.