Dollond, 1825 c.
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Basic Info

Maker: Dollond

Year: 1825 c.

Year Range: -

Year Notes:

Manufacturing Location: London, England

Signature: Dollond / London

Signature Notes:

Inscriptions:

No stand present.

Collection: Adler Planetarium and Astronomy Museum

Accession #: W-181

Sources:

Project investigation and collection website

Public Notes:

Main tube is wood, possibly mahogany. Brass mount for objective glass has milled edges. Brass end cap with dust slide has maker's signature. Brass ferrule at other end of main tube. The one brass draw tube is the erector unit, complete with eyepiece. Unit unscrews at various points for access to lenses (5). Extension ring etched on tube. Brass end cap has dust slide. All visible brass features have milled edges.

Open length is 407 mm - 450 mm, closed length is 264 mm by 34 mm in diameter.

Length (open): 407 mm - 450 mm

Length (closed): 264 mm by 34 mm diameter

F-ratio:

Exit pupil:

Object status:

Optical Basics

Objective type: doublet (crown forward)

Optical style

Physical style spyglass

Functional style

Materials: wood, glass, brass, mahogany

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.:
Complete 3.82 261.90 16.00

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 30.10
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 31.70
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
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 73.50
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 27.29