Unknown, Italian or possibly French, 1630 c.
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photo - whole telescope
Basic Info

Maker: Unknown, Italian or possibly French

Year: 1630 c.

Year Range: -

Year Notes:

Manufacturing Location: Italy or France


Signature Notes:


No stand present.

Collection: Adler Planetarium and Astronomy Museum

Accession #: M-421


Public Notes:

Trumpet-shaped main tube covered with gold-tooled brown leather. Five draws with equi-diameter ferrules. Large objective lens stopped down by a leather-covered diaphragm with gold sunburst motif. Edges of lens are chipped all around.

Since the tube length of the telescope is approximately equal to the focal length of the objective, it was most likely a Galilean form telescope. Its original eyepiece was therefore a simple negative lens but it has been replaced by an irregular shaped piece of poor quality glass with little or no optical power. It was most likely added only for display and serves no optical function in the telescope.

Length (open): 700 mm

Length (closed): 268 mm by 76 mm diameter


Exit pupil:

Object status:

Optical Basics

Objective type: singlet

Optical style

Physical style spyglass

Functional style

Materials: leather, pasteboard, glass, gold tooling

Optical/Lab Data

Drawtube data:

Drawtube notes:

Objective Data

CA curvature (diopters): CB curvature (diopters): PD lens power (diopters): fD focal length (mm): t thickness (mm): free aperture (mm): full aperture (mm): nD refractive index: ν Abbe No.:
Lens 1 1.79 ± 0.0014 -0.81 ± 0.0014 1.37 ± 0.006 731.00 ± 3 2.00 27.00 1.53 55.00 ± 2