Dolland [?], 1800 c.
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Photo

diagram
Basic Info

Maker: Dolland [?]

Year: 1800 c.

Year Range: -

Year Notes:

Manufacturing Location: England

Signature:

Signature Notes:

Inscriptions:

No stand present.

Collection: Adler Planetarium and Astronomy Museum

Accession #: M-455

Sources:

Project investigation

Public Notes:

Main tube is 45 mm in diameter and covered in shagreen. Achromatic objective glass. Brass mount for objective glass; brass cap at objective end. Cap missing from eyepiece end. Four draw tubes of cardboard covered in green paper with brass ferrules. All ferrules, mounts, and the end cap have milled edges. Inside second draw tube is English handwriting. Three-lens erector tube of lignum vitae. All draw tubes have extension marks drawn in black ink.

Length (open): 1020

Length (closed): 285

F-ratio:

Exit pupil:

Object status:

Optical Basics

Objective type: singlet

Optical style

Physical style spyglass

Functional style

Materials: paper, shagreen, wood, 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 1.25 798.00 83.50
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 1 102.30
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 54.30
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
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 54.80
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