Archeoastronomy and World Cosmology

Astronomy 6, Spring 2008Pomona College

Short Assignment #1: Sky Motions and Stonehenge – Due Thursday, January 31, 2008

Quotes for thought –

“We do not ask for what purpose the birds do sing, for song is their pleasure since they were created for singing. Similarly, we ought not to ask why the human mind troubles to fathom the secrets of the heavens… The diversity of the phenomena of Nature is so great, and the treasures hidden in the heavens so rich, precisely in order that the human mind shall never be lacking in fresh nourishment”

Johannes Kepler, Mysterium Cosmographicum,

quoted in Carl Sagan’s Cosmos.

Complete readings in Aveni (p. 1-47) and Krupp as described in the syllabus. Then answer the following questions:

a). Draw a side view of the Meridian as viewed from Claremont, with the important features of the celestial sphere abeled with numbers coinciding with the declination on the celestial sphere. This should include the (flat) local horizon, the North Celestial Pole, The zenith, the Celestial Equator, the range of solar heights during the year, and the declination of the Southern Horizon. What declinations never rise in Claremont? What declinations never set?

b). Go outside on one of these clear winter nights – find the constellations Orion, Gemini, Auriga, Sirius, Mars, and Saturn. If you go out sunset, you should be able to find Mars, which will be “transiting” and a bright red star high toward the South. Later at night, you will see Saturn to your left rising around 11PM (see sky chart) You can find Orion with the three belt stars, and then use this as a landmark to find the other objects. Now come back a bit later (maybe an hour later) and observe the motions of the sky – how far (compared to your outstretched hand) do you think the constellations move in an hour?

c). While you are outside record what you see, and what you think. What thoughts come to mind as you gaze at the planets (worlds apart from ours, hundreds of millions of miles away) and the stars (other suns light years, or trillions of miles away!). How is your viewing of the sky tonight different or similar to the view that ancient people would behold? List a few similarities and differences.

d). In front of our classroom, between the Lincoln Edmunds buildings and Andrew, there is a plan to install a sun dial. Using your knowledge from class, determine the angles of the maximum altitude and minimum altitude of the noon sun. Then use this information and some trigonometry to determine how long the noon shadows for our sundial will be if the gnomon is 2-meters tall. Please include a diagram of the gnomon and the noon sun, at the minimum and maximum heights, with the dates labeled. Where is the mid-point sun height, and what dates will the sun be at this location?

Figure 1: Sky Chart for Claremont for Jan 24, at 6:22PM

Figure 2: Sky Chart for Claremont for Jan 24, at 9:40PM