Homework 3: Due Monday, February 16

1. Where on Earth would you have to be for the celestial equator to pass through your zenith? Where would you be if the celestial equator lay on your horizon? Where would you be if the North Celestial Pole was at the zenith?
2. At what time does the star Betelgeuse (in Orion) transit as viewed from Northfield on February 14? What is its altitude at the time that it transits? What is the declination of Betelgeuse? Does the altitude of Beltelgeuse change over the course of the night? Does the declination of Betelgeuse change over the night? How many times a night does Betelgeuse transit? Does the altitude of Betelgeuse at the time of transit depend on the date? Explain your answers. Use your Starry Nights software and your star maps to answer this question.
3. Now look at the nightly motion of the star Alnitak (the leftmost star in the belt of Orion), again using your Starry Nights software. Where does Alnitak rise (give a compass direction here)? Where does it set? Does your answer depend on the date? Does your answer depend on your location on the earth? What is the declination of stars that rise due east and set due west?
4. On the Starry Nights menu select Guides: Celestial Grid, then fill in the blanks. Stars with a declination between _______ and ________ are circumpolar when viewed from Northfield.