Dollond, 1810 c.
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Basic Info

Maker: Dollond

Year: 1810 c.

Year Range: 1800-1825

Year Notes:

Manufacturing Location: England

Signature: Dollond London / Day or Night

Signature Notes:

Inscriptions:

No stand present.

Collection: Adler Planetarium and Astronomy Museum

Accession #: A-149

Sources:

Project investigation

Public Notes:

Main tube is 64 mm in diameter and made of wood, covered in plain cowhide in poor condition. Cowhide has stitched seam. Objective glass is almost certainly non-achromatic(possibly a replacement); glass has brass mount. Mount is covered by brass sleeve. Brass eyepiece cap has pivoting dust slide. Eyepiece lens has brass mount. Single draw tube divides for holding a tube with two positive lenses, one aperture disc. Draw tube has triple extension marks. Maker's signature on the draw tube.

Length (open): 800

Length (closed): 526

F-ratio:

Exit pupil:

Object status:

Optical Basics

Objective type: singlet

Optical style

Physical style spyglass

Functional style day or night

Materials: leather, 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 7.62 -3.79 6.34 ± 0.012 157.60 ± 0.3 39.70 1.56
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 60.00
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 79.40
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 79.00