ASTRO 103 Chapter Notes - Chapter 1: Orbital Period, Starset

• School: Iowa State University
• Department: Astronomy and Astrophysics
• Course: ASTRO 103
• Professor: Amanda Weinstein

Document Summary

The posiion of the sunrise shits along the horizon over the course of a year. The posiion of sunset also shits by the same amount. These observaions could then be used to set up a calendar for the year. Rising and seing posiions of stars don"t change over a year, the rising and seing imes change. Star sets (and rises) 4 minutes earlier per day. 24 hours per year (same ime on same date every year) Diferent constellaions are up in the evening at diferent imes of the year. Winter evenings: orion, taurus, gemini, canis major and minor. Heliacal rising: the irst ime that a certain star could be seen in the glow of morning twilight, rising ahead of the sun (another ancient calendar marker) Passes through one constellaion every 2 months and shows up in evening sky about once every 2 years. Neptune and pluto move very slowly with respect to the stars.