Professor Vorwald MET 102 Sun’s Path Worksheet

Name

The Change in the Sun’s Apparent Path with Seasons

The diagram below represents a model of the celestial sphere for an observer at 41.8 North. Arcs AB,o

CD, and EF represent the apparent path of the Sun as seen on three different days of the year. The altitude ofPolaris is indicated.

Zenith

West

1. Label the horizon. East Horizon

2. Label east (90 azimuth) and west (270 azimuth).o o

3. Label the zenith.

4. Draw an arrow from the horizon that shows the altitude to Polaris.

5. Draw arrows on each arc indicating the apparent direction of the Sun’s apparent daily motion.

6. Draw a line from the observer to Solar noon on the arc that follows the celestial equator of the sky.

7. Which letters show the positions of sunrise? A, C, and E

8. Which arc shows sunrise in the northeast and sunset in the northwest? E-F

9. The path represented by arc AB is for the first day of which season? Winter

10. The daily path of the Sun on an equinox is shown by which arc? C-D

11. Based on the exact altitude of Polaris and the apparent movement of the noon Sun throughout the year of+23.5 and -23.5 relative to the celestial equatoro o , calculate the maximum and minimum altitude of thenoon Sun during the year. Altitude of the Celestial Equator is 48.2 (180 - 41.2 - 90 ) o o o o

Maximum Altitude 71.7o Minimum Altitude 24.7o

48.2 o +23.5 o 48.2 o - 23.5 o

12. What real Earth motion is responsible for the apparent daily path of the Sun? Rotation

13. What real Earth motion causes the seasonal change in the Sun’s apparent daily path? Revolution

14. If the inclination of Earth’s axis was 50 what would be the effect on the altitude of the Sun at solar noono

on June 21? The altitude of Polaris would be 50 making the altitude of the sky equator lower (40 ). The Suno o

would be 23.5 higher than the sky equator (only 63.5 ). This is lower than the present-day altitude on this date.o o