26. 8-foot Germanic telescope
Germany, 1702
author unknown
tube in pasteboard with wooden case [Inv. MdS-40], tube in tin [Inv. MdS-162]
length tube 276 cm, diameter 9 cm
object lens (attribution uncertain) [Inv. MdS-31]: focal length 350 cm, diameter 6.7 cm

A letter of Manfredi to Marsili, dated 10 January 1702, mentions how some instruments, including a wooden sextant and two telescopes, were given to the same Manfredi by Filippo, brother of Marsili.
Both the 1703 inventory of the instruments in the Marsili Specola and the 1712 Instrumentum donationis mention two Germanic telescopes: "Telescopium aliud Germanicum incerti Artificis, duobus convexis perspicillis, tubo ferreo pedum Bonon. 7 unc. 3, litera A distinctum. Huic etiam suus est tubus chartaceus, thecae ligneae inclusus, quae eodem charactere notatur, intra quem duae oculares lentes aliae repositae sunt, terrestribus objectis inspiciendis. Aliud eadem forma, structura, & magnitudine Telescopium, litera B insignatum, cui tubus quoque alter chartaceus convenit, capsula pariter lignea, eodem Charactere B distincta, conclusus, cum ocularibus duobus ad usum antea dictum."
Just one of the two pasteboard tubes remains, complete with turned wood case. The surviving green-colored six-draw telescope (length when closed 61 cm), does not appear to be worse for wear, which suggests that the two telescopes were new when they reached Manfredi and that the extant tube was used very little.
Similarly, only one of the two tin tubes, that telescopes were normally fitted with to make them easier to use, remains - most likely the one belonging to the sole surviving telescope, 276 cm long, or 7.3 Bolognese feet - closed by a screw cap over the object lens, identifiable by the gradual widening of the two diaphragms inside the tube.
There also remains an object glass without any writing on it (diameter 67 mm, thickness at edge 5 mm, and focus 350 cm), made of green-tinted glass with very few bubbles, one of which is quite large; the object glass is large enough in diameter to fit the still extant mounting on the extendible tube. Its focus, however, appears too long for the instrument even though the actual length of the telescope is unknown since it has been impossible to open the tube. This lens, moreover, fits in well with the length of two telescopic tubes [file 32] in pasteboard, which could be part of the long "tubus chartaceus" of Geminiano Montanariís 11.6-foot telescope.
The eye-piece had a 69 mm focus and consisted of a 52 mm diameter lens, the field being limited to 31 mm by a diaphragm. The distance of the eye-piece lens from the hole for the eye was 44 mm.

E. Baiada, A. Braccesi (1983), p. 84.
G. L'E. Turner, (1991), p. 412.