photo - whole telescope

Maker: Stolle, Heinrich

Year: 1626

Year Range: -

Year Notes: Maker Heinrich Stolle died in 1626.

Manufacturing Location: Prague, Czech Republic

Signature: Henr. Stolle Vhrm. prag fecit

Signature Notes:

located on base of brass cylindrical case

Inscriptions:

No stand present.

Collection: British Museum

Accession #: 1890,0209.2

Sources:

For additional information on this instrument, see Marvin Bolt & Michael Korey, "The world's oldest telescopes," in THE ORIGINS OF THE TELESCOPE (Amsterdam 2010), p. 235-7.

Public Notes:

Signature on case.

Pasteboard etui 88.5 long, diam 25.0. Brass container with crown 83.7, diam 18.2. With the crown the collapsed telescope fits well into the leather etui; without it, not. Starside end of Draws 1, 2, and 3 has brass washer; the inner diameter of each draw is larger than the opening of its washer. Optical length determined for target at 142 paces (MK). Two extension marks on each draw: (1) 5.5, 28.6; (2) 6.7, 23.5; (3) 5.4, 30.0. This leads to total optical lengths of 180 mm (no image visible at this length) for the leftmost extension marks and 119.5 - 121.7 mm for the rightmost marks. When focused at distant object, the telescope is about 117 mm long. Direct measurement using a collimated beam yielded a focal length of 160 mm vs 169 mm measured by Rolf Willach. The latter measurement implies an eyepiece focal length of 52 mm, and a magnification of 3.25, consistent with our observations.

Objective Notes:
Focal length measured first directly with card in large collimated beam. Gasket off-center. Grozed. Gives triple image (one dominant).

Length (open): 117

Length (closed): 63

F-ratio: 18.78

Exit pupil: 2.77

Object status:

Objective type: singlet

Optical style galilean

Physical style spyglass

Functional style

Materials: brass, leather, glass, pasteboard

Drawtube data:

physical lengths in mm: 52.4, 49.4, 49.3, 52.7
starside to extension mark: 28.6, 23.5, 30
star-side tube diameter: 13.1, 11.8, 10.7, 9.4
eye-side tube diameter: 13.1, 11.8, 10.7, 9.4
ring diameter: 15, 15.1, 14.9, 13.2

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	87.49	12350449.21	6.29	169.00	2.76	9.00	12.40

Eyepieces

Notes:

Beveled.

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	-52.00	4.70	11.90		-59.16	123503.71	3.25		1.15