18. Transit telescope by V.F. Stancari
Bologna, 1708
Vittorio Francesco Stancari (Bologna 1678-1709)
length of telescope c. 75 cm
[Inv. MdS-20]

The few seconds difference between the transit times of the Sun across the string meridian [file 3] and those observed with the mural semicircle of Lusverg [file 16] encouraged Stancari to design a completely new instrument: the so-called transit telescope. Developed by Stancari at the same time as Römer and Halley, this instrument would have made it possible to follow the arc of the meridian without any irregularities.
Owing to the death of Stancari in 1709, however, the instrument was not fully completed, even if the operations necessary for its rectification were described exactly by Manfredi in his 1715 Introductio in Ephemerides.

"Telescopium lentis suis instructum - hence his description of it as Instrumentum donationis of 1712 - pedes duos longum (c. 75 cm), hastae fereae alligatum, e cuius medio axis auricalceus assurgit figura conica, foramini etiam conico inserendus, atque ita collocandus, ut Telescopium juxta Meridiani planum moveatur; Quae Machina a Stancario excogitata fuerat, sed nonnullis ad ejus usum pertinentibus destituitur".
The support rod is all that remains today. Already in 1843 the lens was missing, today the telescope too.

E. Baiada, A. Braccesi (1983), p. 87.