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Dolland, 1800 c.+25
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Basic Info

Maker: Dolland

Year: 1800 c.+25

Year Range: -

Year Notes:

Manufacturing Location: London, England

Signature: DOLLOND / LONDON

Signature Notes:

Inscriptions:

No stand present.

Collection: Adler Planetarium and Astronomy Museum

Accession #: M-457

Sources:

Project investigation and website

Public Notes:

Main tube is 40 mm in diameter and covered with shagreen, with brass ferrules. Inside of tube lined in paper with ink writing (English: appears to be lists). Achromatic objective lens mounted in brass, cracked near edge, plano on eye side. Brass end caps with dust slides. Three draw tubes covered in green vellum, each with one extension mark. Brass ferrules. Maker's inscription on third draw tube. Eyepiece is brass mounted and inset in erector unit, and could not be removed for further inspection. Two other lenses in erector unit are mounted in lignum vitae. Paper on erector is colored in blue waves, and there is some ink writing (illegible) on it.

Length (open): 720

Length (closed): 248

F-ratio:

Exit pupil:

Object status:

Optical Basics

Objective type: singlet

Optical style

Physical style spyglass

Functional style

Materials: lignum vitae, shagreen, vellum, glass, 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 1.92 520.50 7.00 25.90
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 88.60
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 44.30
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 54.60
Eyepiece 4
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 49.40
Eyepiece 5
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 34.80
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