Christiaan Huygens – A family affair - Proeven van Vroeger

England in November 1658 346 and was asked by Christiaan to offer one to the King of France
three years later (Nov. 1661). Though I have not found a reference, it seems to be plausible
that the Elector of Brandenburg also received a telescope from Constantijn Sr.’s hands. 347
The father’s important role in showing the instrument to courtly groups – which we
will see shortly – was accompanied by a need for new and better versions of the instrument. In
1662, between his second and third trip to Paris, Christiaan wrote his brother Lodewijk from
The Hague with the message that his father (who was in Paris, together with Lodewijk)
wanted a bigger telescope than the one that Constantijn Jr. had made for him, so that
Lodewijk should keep the older, smaller version – “because of the secret of the invention” –
after Constantijn Sr. had received the new one by mail. 348 (A nice detail: Christiaan expected
that Constantijn Sr. would not be prepared to give away his telescope to Lodewijk unless he
had received a new one. 349 )
In his role as Christiaan’s “high representative” in London and Paris (see below),
Constantijn Sr. did not take a passive stance. For instance, when the Campani-brothers made
new claims about Saturn and Jupiter – distinguishing shadows on Saturn and Jupiter as
Christiaan’s respectively Galileo’s theory demanded 350 – and copies of the new telescope of the
Campani’s were sent out over Europe at the end of 1664, Constantijn Sr. was the first to know
about it and arranged to obtain one. Christiaan had to await Constantijn’s written descriptions
of Campani’s telescope to enable him to make a judgment on the competing telescope –
apparently a task that Christiaan entrusted to him 351 – while his father was showing the
instrument, together with Christiaan’s microscope, to the Parisian societies. 352
346
HUYGENS, C. (1911) BW., Vol. V, No. 5592 (Oct. 14, 1658) – Constantijn Sr. to the King of
England (14 Oct. 1658)
347
HUYGENS, C. (1888) OC., Vol. IV, No. 996 (Mar. 15, 1662); No. 920 (Nov. 23, 1661): “La Lunette
a ce qui me semble court grande risque, s’il faut que Sire Louis la voie; car il sera tenu de dire qu’elle est
fort bonne et mon Pere qu’elle est a Sa Majesté si elle l’agree.”
348
Ibid., Vol. IV, No. 1066 (Sept. 28, 1662); No. 1058 (Sept. 7, 1662): Christiaan to Lodewijk: “Mon
Pere desire d’avoir une lunette plus grande que celle que mon frere luy a faite, la quelle seconde, lors
qu’elle sera venue, vous aurez l’autre si vous voulez, car d’en faire present a quelqu’autre il n’a garde, a
cause du secret de l’invention. Que si’l en arrive autrement, je verray ce que je seray pour vous.”
349
Ibid., Vol. IV, No. 1066 (Sept. 28, 1662). “Quelque bonne qu’el signor Padre trouue la nouuelle
lunette je ne doute pas qu’il ne vous la cede, après qu’il aura receu l’autre.”
350
Ibid., Vol. V, No. 1260 – P. Petit to Christiaan (Oct. 1664): “Vous auez veu aussi bien que nous a ce
que Ma dit Monsieur vostre Pere lescrit de ce nouueau lunetier de Rome Joseph Campanus qui a
obserué Saturne auec des Ombres telles que vostre Hypothese les demande & Juppiter auec deux
Manches ou ombres de ses satellites comme porte sa figure.” According to astronomical theory, a
shadow of the ring was expected on the body of Saturn, and also a shadow of the body of Saturn on its
ring. In the case of Jupiter, four smaller shadows were expected on the planet’s body.
351
Christiaan trusted more often on the descriptions of his father of instruments of others. For instance:
Ibid., Vol. IV, No. 1067 (Oct. 5, 1662), where Christiaan mentions that he has received a description by
his father of Petit’s new and smaller telescopes. In this case, Christiaan initially expressed some
101