Catalogue of Medieval Astronomical Instruments

by David A. King

Yemen Update 30/31(1992):15,35

[The following is excerpted from an article by Prof. David A. King in the Bulletin of the Scientific Instrument Society 31 (December, 1991), pp. 3-7. Among the instruments described are several made in Yemen]

A catalogue of medieval Islamic and European astronomical instruments is currently being prepared at the Institute for the History of Science at Frankfurt University. It is hoped that this catalogue will serve as a useful research tool by providing critical descriptions of all historically-significant instruments, arranged according to provenance and type.

The total number of instruments included in the catalogue will be about 550 astrolabes (some 300 Islamic and 250European) and 250 quadrants, sundials and other instruments...

The basic philosophy behind the preparation of the catalogue is that it is essential to hold the instrument in one’s hands, to take it apart, to examine each part carefully -- in short, to play with it for a while-- in order to begin to understand it properly. Photographs are inadequate for this purpose, but in some cases must suffice. One may need to examine some details with a magnifying glass, or even a microscope. The task for the unsigned and undated instruments is then to relate them to a school or a period. Again it is particularly useful, but rarely possible, to examine related instruments together.

Important collections have already been visited and most of the early Islamic and European instruments inspected and described. A substantial amount of the basic descriptive work (perhaps one-half of the total required) has been carried out. The planned critical analysis of this vast corpus of material can only be conducted when more of the descriptive work has-been completed. Good-quality photographs are already available for only about one-fifth of the instruments, but about four-fifths have been studied, mainly by inspecting the actual instruments and in some cases using published or unpublished photographs.

The catalogue is arranged according to the following general categories (* indicates that only selected instruments will be treated in detail): 1. Early Eastern astrolabes; 2. Late Eastern astrolabes*; 3. Eastern quadrants; 4.Eastern sundials; 5. Misc. Eastern instruments*; 6. Early European astrolabes (to ca. 1500); 7. Late European astrolabes (to ca. 1600);8. Early European quadrants; 9. Early European sundials; 10. Misc. early European instruments*...

Numerous fakes will be featured in the catalogue, and carefully distinguished as such. On the other hand, several instruments generally regarded as fakes will be reinstated as genuine medieval instruments. A regrettable trend amongst the cognoscienti has been to brand as fake any instrument that did not fit their notions of medieval instrumentation...

The advantages to be gained by inspecting large numbers of mainly uncatalogued and unpublished historical objects at first hand will be obvious to any historian. The various Islamic traditions of instrument making can now be related to the history of astronomy in general in the various parts of the Islamic world. We can see the innovations made to the standard astrolabe in Baghdad in the ninth and tenth centuries, and can pursue the development of universal astrolabes and plates in Islamic astronomy.

The cost of photography for this project is enormous, far beyond the means of a small institute. Several museums have already contributed photographic materials without charge, and it is hoped that others will follow suit... The text of the catalogue is being prepared on a computer (MS Word 4.0 on an Apple Macintosh LC), and the standardized format for the entries can be changed at will for the entire text... The text currently amounts to about 2,500pages. But it is easier to begin such a catalogue than to complete it, and in order to produce a final camera-ready copy for publication, additional funding is currently being sought...

The completion of this catalogue will surely stimulate renewed interest in a field which is of prime importance in the history of science. The unity of medieval astronomical instrumentation in the Islamic East and the Christian West will become apparent, and the Islamic and early European contributions to instrument-making will become clear as never before...

[Prof. King can be reached at: Institutfür Geschichte der Naturwissenschaften, Universität Johann Wolfgang Goethe, 6000 Frankfurt am Main, Republic of Germany. He has recently received a substantial grant from the Deutsche Forschungs- gemeinschaft to fund three assistants for two years, as well as limited funding for travel to museums and procurement of photographs.]

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