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Session 27 - Astronomies and Cultures (HAD).
Oral session, Monday, January 15
Salon del Rey Central, Hilton

[27.04] Historical Planetary Astronomy

T. A. Hockey (U. Northern Iowa)

Historical planetary astronomy refers to attempts to use archival physical descriptions and depictions of the Moon and planets to help solve modern problems in planetary science. These data are usually qualitative in nature, most often coming to us in the form of telescopic observers' reports and drawings made in the seventeenth, eighteenth, and nineteenth centuries. For this reason, such data must be treated differently from more-modern photographic and digital imagery.

Most useful historical records come from the telescopic (but pre-photographic) era. However, the eyewitness account, in the year 1178, of what may have been a large, crater-producing impact on the Moon, dates as the earliest historical datum applied to lunar science.

The studies of lunar transient phenomena (LTPs), and of the "ashen light" on Venus, also benefit from a body of historical records. Other examples that I will discuss include attempts to determine if a periodicity exists in the appearance of major dust storms on Mars and attempts to understand the seeming periodicity of the appearance of large, white spots in the northern latitudes of Saturn. I also will discuss my own attempts to use the historical record to search for past jovian features similar to those produced by the collision of comet P/Shoemaker-Levy 9 and Jupiter in 1994.

I will conclude by listing a number of "filters" through which historical data necessarily pass before becoming of use to modern astronomers. These considerations are: 1) resolution, 2) instrumentation, 3) observing conditions, 4) observing technique, 5) observers' experience, 6) observers' purpose, 7) language, and 8) observer objectivity. Recognition of them is necessary to assess the quality of historical records and their applicability to a given astronomical problem. These "filters" will be illustrated by applying them to the example problems described above.

Program listing for Monday