ASTR 130: INTRO TO ARCHAEOASTRONOMY

REVIEW QUESTIONS Tuesday, Dec 1, 2009

Review the context for the following terms

1. planisphere

2. tzolkin

3. circumpolar stars

4. culmination

5. zenith star

6. zenith passing

7. gnomon

8. ceque

9. calendar round

10. haab

11. supernumber

12. precession

13. heliacal rising

14. solstice

15. lunar standstill

16. stone island

17. star compass

18. synodic month

19. eclipse year

20. long count

21. saros cycle

22. pole star

23. solstice

1 24. place-value notation

25. Mul-Apin

26. Dresden Codex Egyptian Astronomy: Egyptians were primarily builders and engineers, who were interested in applying astronomy or interpreting the layout of the sky in astrological symbolic relations. There are a few famous examples of astronomical orientation and alignments, and in the influence of astronomy on time-keeping and calendar systems.

1. A famous example of early astronomical calendars in Egypt is the use of the star, Sirius, to predict the yearly flooding of the Nile. Outline the method that was used and the principle behind it.

2. Star clocks found on the lids of coffins outlined a way to mark the different hours of the night. Briefly outline how the visible ‘decan’ stars could be used to estimate time.

3. The present-day pole star is Polaris, in the constellation of Ursa Minor, but at the time the first pyramids were constructed around 2600 B.C. the pole star was Thuban, in the constellation of Draco. What effect is responsible for this? Roughly when will Thuban agan be the pole star?

4. The pyramids are oriented to the cardinal directions. What is the evidence that the Egyp- tians might have used the rising and setting positions of stars to orient the pyramids?

5. In the Osiris myth, what constellation represented the reborn god? How was this myth reflected in the alignment of the passages from the King’s Chamber in the Great Pyramid towards points in the sky?

Babylonian Astronomy: The Babylonians were responsible for much of our present traditions of time-keeping and units: the 60 divisions of minutes within an hour, or in the angular measurement of a degree, the 360 degree round of a full circle, and the designated constellations of our zodiac. They made accurate estimates of the non-uniform motion of the Sun and Moon, and were able to deduce a detailed system to predict eclipses and the motions ofplanests from their long-standing records.

1. The Babylonians used a sexegesimal system of mathematics. Give a brief description of how this worked.

2. The early records of the Babylonians allowed them to make fairly precise estimates of both the length of the lunar cycle (synodic month) and the motion of the Sun along the ecliptic. Using the formula of 235 lunar synodic months = 19 years, determine the number of fractional lunar months in the year. Why is a 19 year cycle used as a baseline?

3. The Babylonians were able to deduce that the Sun did not move uniformly in its orbit throughout the year. When did it move fastest?

2 4. The Mul-Apin tables give early positions of stars in a rough arrangement (that can also be depicted on a planisphere). Briefly describe this arrangement.

Chinese Astronomy: The Chinese maintained the longest stretch of continuous written records of astronomy, includ- ing such diverse topics as comets, sunspots, novae, and eclipses, as well as star maps and the records of the orderly motions of the planets. They recorded the famous supernova of 1054 A.D. in the Crab Nebula. A number of technological innovations, such as armillary spheres and observatories such as the one at Gao Cheng, allowed them to perform precises observations.

1. One of the contributions of early Chinese astronomers was a precise system of positional astronomy and accurate star maps. How did they specify the position of stars (e.g., for the Suchow planishere)?

2. What cultural issues led the Chinese to make royal astronomers civil service appoint- ments? How was this reflected in the type of observations they recorded?

3. What factors may have led the Chinese, Koreans, and their neighbors to emphasize the pole star in their astronomy? In what way did this show up?

4. A technological achievement that predated the clock drive of modern telescopes was the use of a mechanically driven armillary sphere in Su Song’s clock tower at Kaifeng to show the current positions of objects in the heavens. Briefly describe the principle behind this device (i.e., what was the model for the armillary sphere)?

European Megaliths: The most famous of these megalithic structures is Stonehenge, which was constructed on an existing burial site starting some few centuries before the pyramids were built. These seem to have largely symbolic value. The orientation of the avenue and heelstone with the summer solstice sunrise is well known. A number of other alignments with lunar rise and set positions at major (and minor) standstill have been proposed.

1. What is the evidence that Stonehenge may have been oriented for reasons of symbolism, rather than being an observatory for the Sun, Moon, and eclipses as Hawkins proposed?

2. Aligned structures such as Stonehenge, Kintraw, and other megalithic sites present chal- lenges for modern astronomers and archaeologists. What are the reasons for these diffi- culties?

3. Newgrange is an example of another neolithic site with a solsticial orientation. Describe how it is oriented. Why do we not believe it is an observatory?

4. In an attempt to look for broad alignment trends, Clive Ruggles studied recumbent stone circles in the UK. What were the results of his studies? How does this fit in with our notions of lunar alignments among megaliths?

3 The Astronomy of the Maya: The Maya were sophisticated astronomers and mathematicians who invented a unique calendar system that reflected interlocking cycles of time. The 260-day tzolkin is the primary calendar. The Dresden Codex records detailed astronomical tables for the planets, especially Venus, and for eclipses.

1. List the three calendar systems used by the Maya. How were they related?

2. Describe the mathematical system of the Maya. (Compare it to the Babylonian system). What was different about the way it was used for calendar calculations?

3. The five aspects of Venus shown in the Dresden Codex are based on an astronomical relation between Venus’ synodic period and the solar year. Describe this relationship, and its implications for a Venus observer who makes regular observations of the planet.

4. What is the evidence that the Maya used Venus to schedule their ‘star wars’?

5. The eclipse tables in the Dresden Codex use intervals of typically 5 or 6 lunar months to predict the next eclipse. What is the astronomical basis for considering this interval a good choice? (What conditions must apply for an eclipse?)

6. Discuss the way that cultural aspects impacted the astronomical tabulations in the Dresden Codex such as: (1) the recorded intervals for the stations of Venus and (2) the correction scheme for the long-term Venus cycles

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