OBSERVATORIES IN LEIDEN AND RECIFE: THE DESIGN, ORGANIZATION AND INSTRUMENTS COMPARED

In an earlier article, we concluded that in Brazil, MARGGRAFE used Leiden Observatory as his benchmark. In Recife, he copied to a large degree the site, instruments, and methods that he had become familiar with when he trained himself in observational astronomy in Leiden. To demonstrate this, we will compare below the design, organization and instruments of both locations.

LOCATION AND BUILDING: 1. LEIDEN

The Leiden Observatory was housed on top of the Academy Building on the Rapenburg canal, with current geographical coordinates 52° 9’ 25” North, 4° 29’ 8” East. The building was an old convent that was seized by the civil authorities of Leiden after the Reformation. It was put in use in 1572 and the building still serves today as the place for events with a ceremonial character, such as graduation ceremonies, inaugural lectures and promotions.

In 1633, a rectangular platform was made on one of the the roofs of the building. The preserved specifications give the dimensions as approximately 18 feet long, 13 feet wide, on a tower 19 feet high. The tower had to be clothed with wooden wainscot, with an occasional window to provide light on the spiral staircase leading to the platform. On this platform, a solid vertical pole was placed, to which the quadrant was mounted in such a way that it could rotate around its axis.

The quadrant was originally set up in the open air. To protect the instrument against wind and weather, it was decided in the spring of 1634 to add to the platform a small octagonal turret, with in its centre a sturdy pole, ‘motionless and standing straight’, so that the quadrant could easily rotate around its centre, in pivots fixed at the bottom and the ceiling of the dome (fig. 85). Unfortunately, the drawing of the architect that accompanied the specifications of the dome is lost. But the text mentions two door frames and four window frames, for ‘looking out’. The dome itself had to be clad with ‘wood paneling’ (wagenschot), one inch thick, with a lead roof. On the sides, it had fourteen shutters, eight to turn upward, and six to drop down.