Ramsden, Jesse, 1780 c.20
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Photo

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Basic Info

Maker: Ramsden, Jesse

Year: 1780 c.20

Year Range: 1760-1800

Year Notes:

Manufacturing Location: London, England

Signature: Ramsden London

Signature Notes:

Inscriptions:

No stand present.

Collection: Adler Planetarium and Astronomy Museum

Accession #: DPW-39

Sources:

Project investigation

Public Notes:

Length (open):

Length (closed): 114 mm by 42 mm diameter

F-ratio:

Exit pupil:

Object status:

Optical Basics

Objective type: singlet

Optical style

Physical style spyglass

Functional style

Materials: brass, glass

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 1.25 ± 0.0016 170.90 ± 0.2 9.70 31.50
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 44.12 3.90
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 21.69 7.90
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 12.83 13.50
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 8.23 20.80