Fig. 75. Portrait of Tycho Brahe.
Fig. 76. Interior of Tycho Brahe’s Observatory at Uranienburg.
His large brass celestial globe, six feet in diameter, was carried back to Copenhagen in the year 1623 by King Christian’s son, Ulrich, and there it was carefully kept until the year 1728, when with the castle in which it had been placed it was destroyed by fire.
Recalling the far-reaching influence of Tycho Brahe on astronomical studies and on celestial globe making, it cannot be without interest to quote here his own reference to his great globe, wherein he describes its construction.
“This globe,” he says,[356] “which is a very large one, we have made with great care, but with none the less than we have employed in all of our others. The interior is of wood with many intersecting circles and special supports, strengthened here and there from the center, and being then fashioned into a spherical shape. As for its parts of wood, these were made at Augsburg in the year 1570 before I returned to my native land, as I found there a capable workman, having sought for a long time elsewhere in vain for such an one. There, on account of its size, which made it difficult to move, it had remained for five years, when I returned to Augsburg; this was in the year 1575 as I came out of Italy on my way to Ratisbon to be present at the coronation of the August Emperor Rudolf II, when I found the globe had been finished some time previously. But its shape (sphericity) did not altogether satisfy me, moreover certain cracks could be seen. In the following year, and not without much difficulty I had it carried to Denmark. There the cracks were filled in and the sphericity made more nearly perfect by laying over the surface about one hundred skins. There followed a testing for a period of two years to ascertain whether the cracks would reappear after two summers and two winters. When, after this test, I saw that it retained its sphericity, I covered it over with thin brass plates of uniform thickness without mishap, and this I did with such care and skill that you would be led to say the globe was made of solid brass, the joinings of the plates being scarcely visible. I next fashioned it into a perfect sphere and marked thereon the zodiac, and the equator with its poles, also the degrees each of sixty minutes by engraved lines as we do in such work. I then left it for the space of one year, as there was some doubt after putting on the brass plates as to whether the globe would retain its sphericity in winter and in summer. When it had been sufficiently tested not only did I indicate the circles of which I have spoken but also all the stars of the eighth sphere I represented in their proper places, as many stars as were to be seen in the heavens, and I increased their number more and more in succeeding years up to 1600. Thus I with purpose added all the stars visible to the naked eye, in their proper places adapted to the year 1600 which was near at hand. And so there passed nearly twenty-five years from the first work on this globe until it was finished, by the addition of its proper divisions and its stars. This delay, although it might seem tedious, was not without its value; for all things were thus done more carefully and better. ‘Work quickly only if you work well.’ Then the outer circles were fitted to it, that is, a meridian and after that a horizon circle. This meridian is made of brass, and each degree is divided into minutes, and the horizon has the width of a palm of the hand, being covered with brass having the degrees and minutes marked. The vertical quadrant passing from the zenith to the horizon is of brass.
“The globe rests on a firm base having two iron supports crossing each other, two of which you see on one side and two on the other. These are for the purpose of giving strength lest the horizon of the instrument should not be firm because of its bulk and weight.
“The entire support is five feet high, and on the lower part of the structure various mathematical devices are to be seen skilfully painted for the sake of ornamentation, and with the other features adding beauty to the whole. The globe itself is approximately six feet in diameter, and from this dimension the size of the meridian, of the horizon and of the rest of the instrument can be obtained.