Astronomy Before the Telescope (2025)

Wednesdays, 7-9 PM, Online
March 26; April 2, 9, 23, 30; May 7

We glimpse astronomy in ancient cultures. What did they observe and regard as important? What beliefs developed and purposes were served? How did they advance the science of astronomy?

We interpret what they saw and emphasized in modern terms. For example, ancients noted the sun rises and sets at changing spots along the eastern and western horizons, marking the progression of one year. Today we explain this by Earth’s rotation, revolution and axis tilt. This is an introductory course. However, familiarity with astronomy basics is helpful as modern explanations are only briefly reviewed.

We introduce the oldest instruments and procedures used to measure distance, size, angle, and time. The class stops at Galileo, ca. 1600, who used the telescope to uncover a totally new astronomy.

COURSE OUTLINE

MARCH 26- ANCIENT ENGLAND AND EGYPT
Archeaoastronomy. Purposes served by ancient astronomy, e.g., rock circles. Key events behind ancient observations: solstices, equinoxes, standstills, eclipses, Egyptian focus and myths about the milky way. Alignment of pyramids. Constellations, calendar, clocks. The merkhet.

APRIL 2- BABYLONIA, GREECE, ETRURIA, ROME
Babylonian astronomy, cultural traits, base-60 number system, impact on Greeks. Emphasis on numbers, data, math patterns… not models. Greeks’ changed focus to physical models, getting size and distance of Earth, moon, sun. Etruria- steeped in astrology, subsequently rejected by Rome. Roman celestial navigation, sundials. Julian calendar (for Julius Caesar) inserts leap year, later improved by Pope Gregory who dictates that 10 dates vanish in 1582.

APRIL 9- INDIAN AND ISLAMIC ASTRONOMY
India fixates on improving the geocentric model and supporting astrology. Accurate description of sun’s analemma and the equation of time. Vivid, speculative cosmology.

Islamic astronomers primarily serve Muslim practices. Development of star maps, sky coordinates, lunar calendar, compass directions, triangulation, trigonometry. Discovery of obliquity and parallax.

APRIL 16– No class.

APRIL 23- MEDIEVAL AND RENAISSANCE EUROPE
Dark ages. Improvement in rate of precession, and “trepidation” of the equinoxes. Copernicus develops heliocentric model and relative planet distances. Work of Brahe and Kepler leads to three laws of planetary motion, having wider applications and then explained by Newton’s physics.

APRIL 30- CHINA, OTHER CULTURES
Astronomy as a part of government. Focus on record-keeping, uncovering periods between events. Lunar calendar intercalations, Metonic cycle. Accurate precession rate. Unique constellations, star maps, “guest” stars, accurate clocks. Some myths and calendars from Central America, Africa, Australia.

MAY 7- IN REVIEW: ANCIENT INSTRUMENTS
Armillary and celestial spheres, astrolabes, merkhets, sundials, cross-staff, sextant, quadrants.

REGISTER HERE: https://aaa.org/event/astronomy-before-the-telescope-2025/2025-03-26/#tribe-tickets__tickets-form
Members $75; Non-members $90

* After registering, you’ll receive a confirmation containing the Google Classroom (GC) link. Click on this immediately to be added to the class roster. Google Classroom contains the key Zoom link to attend class each week, which opens around 6:50 PM and starts at 7:00 PM. GC is also used for posting selected slides, supplementary materials, announcements, discussions between the instructor and classmates, and class recordings (posted within a day).

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Astronomy Before the Telescope (2025)