Unknown
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Photo

photo - whole telescope
Basic Info

Maker: Unknown

Year:

Year Range: 1675-1750

Year Notes:

Manufacturing Location: France

Signature:

Signature Notes:

Inscriptions:

No stand present.

Collection: Adler Planetarium and Astronomy Museum

Accession #: M-456

Sources:

Project investigation

Public Notes:

Similar to M-422. Objective of dubious origin. Four draw tubes.

Length (open):

Length (closed): 317

F-ratio:

Exit pupil:

Object status:

Optical Basics

Objective type: singlet

Optical style

Physical style spyglass

Functional style

Materials: wood, shagreen, glass, rayskin, pasteboard, vellum, leather, 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 2.84 ± 0.01 ± 0.01 1.46 ± 0.005 685.50 ± 0.2 27.00 1.51 ± 0.003 61.00 ± 3
Complete

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 28.60 24.00
Lens 2 44.60 ± 0.3
Lens 3 52.40 ± 0.4
Lens 4 38.00 ± 0.2
Eyepiece 2
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 52.40
Eyepiece 3
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 38.00