photo - whole telescope

Maker: Bourgeois, Jacques

Year: 1680 c.

Year Range: -

Year Notes:

Manufacturing Location: France

Signature: IB

Signature Notes:

Inscriptions:

No stand present.

Collection: Coll. Willach

Accession #: RW 022 [2622] [] [2023]

Sources:

Project investigation.

Public Notes:

This is "IB" signed telescope is likely by Jacques Bourgeois. Signed "IB" at both ends of the main tube. Three lens eyepiece, with ocular lens in one unit and the other two in another unit, separations 130 mm and 230 mm. The objective is likely a biconvex lens. Image is fairly good, and clear.

This is almost identical to LC 22 from the Louwman Collection. LC 22 can be found in Louwman, and Zuidervaart, 2013 p.39.

Length (open): 2660

Length (closed):

F-ratio:

Exit pupil:

Object status:

Objective type: unconfirmed

Optical style

Physical style

Functional style

Materials: horn, leather, parchment, wood, glass, gold tooling

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							34.00

Eyepieces

Notes:

Eyepiece 1

	fD focal length (mm):	free aperture (mm):	full aperture (mm):	s spacing (mm):	CA curvature (diopters):	CB curvature (diopters):	M magnification:	FOV field of view (degrees):	Thickness:
Lens 1				210.00