Unknown, 1680 c.10
Coll. Willach Arrow right Arrow left

photo - whole telescope
Basic Info

Maker: Unknown

Year: 1680 c.10

Year Range: -

Year Notes:

Manufacturing Location:


Signature Notes:


No stand present.

Collection: Coll. Willach

Accession #: 2642


Project investigation

Public Notes:

Only known 4 lens reverse taper. Wallpaper kliester indicates French or Italian origin. Unusual in that most reverse tapers are English. Point of reverse taper is that large eye lens gives large field of view. Possible maker Cherubin d'Orleans but no evidence. Tooling is unique, nothing similar has yet been found. Early Campani is combed marble. Later have some wallpaper marbling. De Rheita establishes the idea of a reverse taper, but d'Orlean makes it better known. De Rheita also proposes the idea of using two eye lenses in order to increase the field of view. De Rheita specialized in binoculars, and d'Orleans, Patroni, and Bailloui make them on the same principle. Large end at the eye, just like a reverse taper. Ends of tube are worn. Proportions in keeping with "La dioptrique oculaire" by Chérubin d'Orléans, père, 1671. Four eyepiece, chromatic compensation (by chance). Erector and field lenses all placed in tube in last 400 mm of main tube (see schematic in RW 1996 Annals of Science Paper).

Length (open): 3040

Length (closed):


Exit pupil:

Object status:

Optical Basics

Objective type: unconfirmed

Optical style terrestrial

Physical style

Functional style

Materials: glass, paper, pasteboard, brass

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 2485.00