Maximilianus Hell (1720-1792) - Munin

Prior to the 1761 transit, Father Hell issued a 20-page monograph with instructions as to how
the transit was to be observed. 49 A lucid text, written in a language accessible even to those
with little previous experience in astronomy, it appears to have been widely disseminated.
This is evident not only from epistolary evidence, 50 but also from the impressive report Hell
was able to compose only a few months after the transit had taken place, „Observation of the
Transit of Venus in front of the Disc of the Sun on 5 June 1761, with Observations of the
same Venus Transit made by Various Skilled Observers throughout Europe, and an Appendix
of Several Other Observations‟, published as an appendix to the Ephemerides Astronomicae
for the year 1762. 51 Not all observers communicated directly with the astronomical giants of
Paris and London. Some shared their data with Maximilianus Hell, leaving it to him to assess
and publish their observations. Internal evidence in Hell‟s text indicates it was printed
sometime during the autumn of 1761, the last reference being to August of that year 52 . By
then, Hell had received letters and printed reports stating the results of observations in Central
Europe as well as Russia, Sweden, Italy, France, Spain and even England, despite the war.
Several of the observers referred to the twenty-page monograph when they reported their
observations. 53
Like his colleagues in Paris and London, Hell had used his position as Imperial and
Royal Astronomer to place orders at the urban instrument makers on behalf of astronomers
living outside Vienna, and to make sure the necessary instruments reached them before the
transit took place. 54 His brief monograph with instructions should be seen in this context,
49 Hell, Transitus Veneris per discum Solis Anni 1761 … [1760].
50 Hell to Lacaille in Paris, 31 January 1761; Hell to Rieger in Madrid, 6 February 1761; Hell to Braun in
St. Petersburg, 8 February 1761; Hell to Chr. Mayer in Heidelberg, 9 February 1761; Messier in Paris to Hell,
[May] 1761; Poleni in Padua to Hell, 25 May 1761. In the first of these letters, to Lacaille, Hell says his work
was meant for learners in astronomy only: “Adjecta transitus Veneris per discum Solis exemplaria tuo arbitrio
inter tyrones Astronomiæ distribues, nam in horum usum solum hæc conscripta volui” = “The copies of the
Transitus Veneris per discum Solis you may distribute as you will among learners of astronomy, it is for their
sake only that I decided to write it”. In a letter dated Paris 18 April 1761, Lacaille confirms to Hell that he has
fulfilled his request. Mayer also commented on the treatise, in a letter to Hell dated Heidelberg 17 April 1761.
51 Hell, “Observatio Transitus Veneris ante discum Solis die 5 ta Junii 1761. …. Adjectis Observationibus ejusdem
Transitus Veneris factis à variis per Europam Viris in observando exercitatis, cum Appendice aliarum
nonnullarum Observationum”, 1761.
52 Hell 1761, p. 89: “Anno 1761. […] mense Augusto”. Unfortunately, I have been unable to track down letters
written in the autumn/winter of 1761-62 that might have shed light on the exact date of publication (cf.
Unprinted sources, 1a and 1b).
53 Cf. Hell 1761, where Hell states his sources for the data of other observers scrupulously. Many of the
handwritten reports on the 1761 transit that were delivered to Hell are still preserved among his manuscripts at
the Wiener Universitätssternwarte (WUS Vienna).
54 Hell to Chr. Mayer in Heidelberg, 9 February, 12 March, and 10 April 1761; Hell to Ximenez in Florence,
18 February 1761; Freyherr Ehrmans zum Schlug to Hell in Vienna, dated Wezlas 8 May 1761. On the lastnamed
person, see Section I.2.2.1.
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