Deák Antal András: A Duna fölfedezése

Tartalom - III.A DANUBIUS PANNONICO-MYSICUS, 1726

T II E DISCOVERY OF THE DANUBE observations in Vienna (15-28 April 1696), in Buda (24-28 May), in Baja (1-6 June), at the mouth of the Dráva - adconfluentes Danubium et Dravum (12-14 June), at Szeged (17 June14 July), at the mouth of the Tisza- in Castris prope Titul (18-25 July), in Szolnok (9-13 August), in Eger (18-21 August) and once more in Buda (24-30 August), that is, from the middle of April to the end of August.

267 He made two observations in Buda. First, he measured 47° 25 and the second time 47° 24'. The latter measurement was included in the comprehensive chart, which was the right choice. Marsigli or possibly Müller also measured the zenith of the sun at the same place.

26

8 Jupiter and its moons were observed in Vienna, in Buda, 4 miles south of Buda, near Gobinum (?)village on the Danube, on an island one and a hall hour's walk down from Tolna, in Baja, at the mouth of the Dráva, in Szeged, Zenta and near Titel in the military camp. Mercury passing in front of the sun was observed in Vienna on the morning of the 3rd of November 1697. He added a picture to illustrate the chart of measurement values. Finally, he listed his lunar observations. He observed and made Müller observe the alterations in the light of the moon in Vienna and in Szeged, at Sablia (Zsablya), in Szolnok, on the bridge over the Zerna (Cserna) swamp near Utvar (Udvar), at Titel and in Eger. The 18 captivating moon depictions were probably made by Eimmart's daughter Clara (1676-1707) to whom about 350 lunar depictions are attributed.

269 The prototypes for these depictions are preserved in the observatory of Bologna. On them, I think I can recognise not only the lady-astronomer's marks but the form of the legend which also matches that published in the book.

27

0 We know from Eimmart's letter

27

1 that Clara sent, as a token of her gratitude, the rest of her drawings of the phases of the planet with the humble request that he accept this small work with grace. At that time, every able person around Eimmart was working on the Danubius. So Clara evidently sent the Moon depictions of Marsigli's book for inspection. It means that the drawings were made not at the end of the 17th century, as cited in the technical literature, but in 1701. Yet another problem emerges with regard to the Moon depictions. Did Clara Eimmart draw the lunar phases observed in Hungary for the copperplate engraver in Nürnberg who had prepared the versions that served as models for Clara. It is obvious that the timed results of the observations made in 1696 at the places listed in the book were noted, not by Clara, but either by Marsigli or someone else. Müller's above-mentioned diary of observations answers this question as well. It contains, namely, lunar depictions drawn by Müller in an arrangement identical to that published in the Danubius.

27

2 He exactly registered the place and time of the observation and sketched the observed phenomena with a pencil. However, he did not depict all of the moon but only the zone of interest with respect to the observation. Thus, the whole process can be reconstructed as the lovely and finely detailed lunar illustrations from the book come to life, first from Müller's sketches and then by Clara's hand. The moon phases were given such great emphasis in the book, because astronomers thought at that time that their accurate observation would help in calculating longitude. They were only able to get correct results, however, if their watch kept good time, if they correctly judged the moment of the 26

7 BUB Mss di Marsigli Vol. 100, Pars I. 268 j

at

a I co

uld find did not always reveal when and where Marsigli himself made the observations. 26

9 Ibid. 2

7^ Bologna, Via Zamboni 33. Inscription: Plenilunium. pinxit ad Archetypum M. C. Eimmarta. Norimb. [Full Moon. Painted as a model by M. C(lara) Eimmart] The author adds the remark to the picture published on the back cover of the guide to the Bologna Astronomical Museum and edited by the Observatory of Bologna, that Clara's father gave Marsigli 10 paintings depicting this celestial body. I am convinced that Clara completed the Moon depictions in the book as well since her father must hav e been extremely burdened by the engraving of the figures for the book.The letter suggests that Heinrich Müller also assisted. 27

1 BUB Mss di Marsigli Vol. 79. p. 20. G. C. Eimmart, Nürnberg, 24. September 1701. 27

2 BUB Mss di Marsigli Vol. 100. Pars. I. pp. 1-47. 142