Yarwell, John, 1690 c.10
Coll. Willach Arrow right Arrow left

photo - whole telescope
Basic Info

Maker: Yarwell, John

Year: 1690 c.10

Year Range: -

Year Notes:

Manufacturing Location: England

Signature: John Yarwell / Fecit

Signature Notes:


No stand present.

Collection: Coll. Willach

Accession #: RW 143 [26143] [2013 11] [2023]


Project investigation

Public Notes:

This a reverse taper. This was updated (parts do not always match up) but likely dates to the end of 17c. Signed by Yarwell, Yarwell always signs with coat of arms. Three-lens eyepiece of unequal spacing. Each lens at end of a tube (normal style) Cardboard on draws and main tubes, covered in gold-stamped parchment; ends are lignum vitae, and ferrules also tooled parchment. These ferrules are typical for English telescopes until Dollond starts using wood. Tooling same pattern as Marshall.

Length (open): 2400

Length (closed):


Exit pupil:

Object status:

Optical Basics

Objective type: unconfirmed

Optical style

Physical style

Functional style

Materials: parchment, glass, pasteboard, lignum vitae, gold tooling

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 0.53 1885.00 37.00 30.00



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 1 100.00 36.00 200.00
Lens 2 97.00 39.00 160.00
Lens 3 69.00 31.50