Lession Guide for Teaching Archeoastronomy
Below are several activities designed to provide experiences in archeoastronomy. The activities may be used for students at a wide range of age and experience levels, and an estimate of the appropriate level is indicated after each activity. Most of these activities require little in the way of materials, and can involve the entire class in sky watching. Simple materials such as sky charts, plastic overlays, tripods and sighting tubes may be obtained in some cases by contacting Dr. Penprase at Pomona College.
The first group of exercises involves examining the artifacts and sky lore of actual ancient cultures. By using actual pictures of rock art, stone monuments, and other artifacts, the students can get a first-hand experience working with the primary materials for the subject of archeoastronomy.
1). Chaco Canyon Supernova Image
Below is a rock art image found on the trail to Penasco Blanco in Chaco Canyon, New Mexico. It has been variously interpreted as a commemoration of a supernova event, or a completely non-astronomical symbol associated with a clan of the Pueblo indians. It is possible to engage the entire class in a lively debate on this topic. In the course of research for the debate, students may be asked to calculate the positions of the moon, stars and planets using one of the many planetarium computer programs available (for the PC, one can use the program "The Sky" or "Dance of the Planets", and for the MAC "Voyager II" works well).
To use the exercise in the class it is necessary to review the available examples of astronomy and sky watching in Native American culture. For background material, the other sections of the web page may be used along with the sources listed below in the bibliography. The rich sky lore, and documented sky watching of the Native Americans should be stressed. The Anasazi people predated any of the present tribes in the Southwest, and built elaborate ritual buildings which were aligned with astronomically derived cardinal directions. In several cases the alignments include small windows which are thought to provide dramatic light and shadow indicators of the solar year. Examples include the Sun Dagger on Fajada Butte, and Casa Rinconada, which has a portal aligned with the sunset at summer solstice.
The class also needs to be informed of the date of the event -- July 4, 1054 AD. The position of the supernova relative to the moon may be precisely determined for the date. One finds that the moon is in approximately the same location of the sky relative to the supernova for this date (The supernova is now the Crab Nebula, or M1). One can locate the horizon in the picture as the corner of the wall; this interpretation is confirmed by the location of the sun symbol visible at lower left on the petroglyph).
Questions to address include:
How significant is the alignment of Moon and "Supernova"?
Here it is important to take note of the fact that the lines up with a given location in the sky at the same date only once every 18.5 years. This cycle is known as the Metonic cycle, and can also be used for predicting eclipeses on earth.
Are there discrepancies in the picture presented?
Here if one notices that the orientation of the crescent moon relative to the horizon is backward and also that the relative positions are not in a very accurate scale making this a very primitive sky chart indeed.
Are there simpler or alternative explainations for the rock art?
Here perhaps the hand is the 1066 appearance of Halley's comet. Or maybe the moon and Venus is depicted. Also it is known (see Williamson, p. 77) that Zuni skywatchers adopted a symbol which included the sun, the moon, the sacred hand and the morning star, which was carved onto rocks. Could this be a similar marking?
"1054 Supernova" rock art, from Chaco Canyon park, New Mexico. The rock art appears on the ceiling of an overhang above a small cave which is known to be a sacred location used in astronomical rituals.
For reference, an image of the sky as plotted by "Voyager II" is shown below. This shows the relative locations of the moon, and the supernova (which is labelled by M1 -- the name for the Crab Nebula).
Williamson, Ray, "Living the Sky - The Cosmos of the American Indian", University of Oklahoma Press, 1987.