Practical Astronomy between Copernicus and Kepler

[Pierre Tavlitzki]

The astrolabe, an instrument developed by Islam, was used to know the time by measuring the position of the sun (during the day) or of a major star (at night) over the horizon. It is a disc graduated with a rotating arm. The reference lines carved on its plate are only valid for a fixed latitude.

The book of Copernicus, in 1543, gave scientists and travelers a taste for the calculations. A new instrument will then be developed, the astronomical compendium. Its main manufacturer was Christopher Schissler. His workshop was in Augsburg.

On 2 December 1999, Sotheby's sold 300 K$ costs included a compendium signed Schissler dated 1556. It is a pocket "computer" 7.6 x 7.6cm x 1.6cm, octagonal, made of gilt brass. Do it! Despite its small size, it included: an astrolabe, a map indicating 120 cities of the Low Countries focusing on Breda and Dordrecht, a sundial, the latitude of 35 cities, a chart to determine the time of sunrise and sunset depending on the latitude, and even a removable vane that the traveler could mount in the center of the plate.

On 11 November 2007, another compendium signed Schissler, undated but made around the same time as the previous one, was sold 620 K € excluding fees by Bayeux Enchères. This copy was of exceptionally large size: 12.2 x 12.2 x 1.8 cm. Octagonal also, it included in addition other accessories such as a compass, a nocturlabe and a lunar calendar.

The example coming on sale on Nov. 29 in Villefranche-sur-Saône by ERA is less prestigious than its two predecessors. Square shaped, it is not signed and it is assumed that it was made in Augsburg circa 1570. This one also is sold with its windvane! It can be seen on page 204 of La Gazette de l'Hôtel Drouot of October 10 and provisionally on the auction ad site Interencheres.

We are far away from the major auction houses: there is no catalog number, no website, no published estimate, and I can not guarantee that I will ever find the result. But I was pleased to present this witness of the art of travel from another time.

To understand where this instrument was in the history of science, consider that still at that time observing the sky was only to the naked eyes. The telescope did not exist.

[Pierre Tavlitzki]

This lot has not been sold. Its estimate was 50 K €.

The other lot that I noted in my weekly preview of Nov. 2 was an English astronomical telescope with eight tubes of the end of the seventeenth century. It was sold 30 K € excluding fees.

[Pierre Tavlitzki]

Do you speak French ?

Here is a video that announced this interesting sale.
Edited by Interencheres.tv