Gregorian reflecting telescope
Date1715-1720
Inventory Number5002
ClassificationTelescope
Subject
Maker
English
Cultural Region
Dimensionsbox mounted, tube horizontal: 24.2 x 19.8 x 42 cm (9 1/2 x 7 13/16 x 16 9/16 in.)
tube: 6 x 6 x 42 cm (2 3/8 x 2 3/8 x 16 9/16 in.)
box: 8.9 x 38.2 x 16.1 cm (3 1/2 x 15 1/16 x 6 5/16 in.)
tube: 6 x 6 x 42 cm (2 3/8 x 2 3/8 x 16 9/16 in.)
box: 8.9 x 38.2 x 16.1 cm (3 1/2 x 15 1/16 x 6 5/16 in.)
Material
Accessoriessolar filter; lens; awl; dust caps.
DescriptionThis brass Gregorian telescope has an altazimuth mounting that attaches it to his original box as well as a heavy-duty awl for boring a hole in a tree or post in order to mount the telescope in the field.
The optical tube has both primary and secondary mirrors present. A hammered brass, triangular spring with a circular aperture is put between the back of the primary mirror and the eyepiece fitting.
There is a pressure fit dust cap with large knurling on the edges and ornamentation of concentric circles. The cover for the eyepiece is of similar design but has finer knurling. There is large knurling at the primary end of the tube. The long focusing screw has a finely knurled head.
The tube is formed of brass covered in three organic layers. The inner layer is vellum. The middle layer is black morocco leather. The outer layer is a modern, black leather "jacket" to protect the two layers below, which were cracking and showing signs of earlier repairs. This "jacket" was added during conservation in 2005.
There is faint lettering scratched through the original varnish on the outside of the breech block. The inside of the same is marked, "XX2." No other marks were found.
The optical tube is attached to the mounting by means of a U-shaped bracket held to the tube with wing screws. The bracket is attached by means of another wing screw to a collar that rotates around the turned central pillar. The collar is held to the pillar by another wing screw and two washers. The pillar screws into a brass plate in the center of the box lid.
The pillar is also pierce by a large hole near its base. A cast iron, key-shaped awl can be inserted through the hole in order to fix the telescope to a tree or fence post in the field.
The fitted box has brass latch hooks, a key plate, and a lock. Parts that touch the telescope are lined with green wool. Accessories in the box include a small wooden, cylindrical box with a small lens (diameter, 2.6 cm), which is a spare for the eyepiece, and a dark glass solar filter (diameter, 2.0 cm). These are wrapped in paper and protected by cotton and crumpled paper.
The optical tube has both primary and secondary mirrors present. A hammered brass, triangular spring with a circular aperture is put between the back of the primary mirror and the eyepiece fitting.
There is a pressure fit dust cap with large knurling on the edges and ornamentation of concentric circles. The cover for the eyepiece is of similar design but has finer knurling. There is large knurling at the primary end of the tube. The long focusing screw has a finely knurled head.
The tube is formed of brass covered in three organic layers. The inner layer is vellum. The middle layer is black morocco leather. The outer layer is a modern, black leather "jacket" to protect the two layers below, which were cracking and showing signs of earlier repairs. This "jacket" was added during conservation in 2005.
There is faint lettering scratched through the original varnish on the outside of the breech block. The inside of the same is marked, "XX2." No other marks were found.
The optical tube is attached to the mounting by means of a U-shaped bracket held to the tube with wing screws. The bracket is attached by means of another wing screw to a collar that rotates around the turned central pillar. The collar is held to the pillar by another wing screw and two washers. The pillar screws into a brass plate in the center of the box lid.
The pillar is also pierce by a large hole near its base. A cast iron, key-shaped awl can be inserted through the hole in order to fix the telescope to a tree or fence post in the field.
The fitted box has brass latch hooks, a key plate, and a lock. Parts that touch the telescope are lined with green wool. Accessories in the box include a small wooden, cylindrical box with a small lens (diameter, 2.6 cm), which is a spare for the eyepiece, and a dark glass solar filter (diameter, 2.0 cm). These are wrapped in paper and protected by cotton and crumpled paper.
In Collection(s)
Signedunsigned
FunctionThis may be the earliest known Gregorian telescope in the world. It is similar to but more complete than a telescope that once belonged to the Earl of Orrery, for which the claim has also been made. That telescope is in Oxford.
ProvenanceEdward Holyoke (Cambridge, Massachusetts) purchased c. 1710; given to his son, Dr. Edward Augustus Holyoke; given to his daughter, Susannah Holyoke Ward; given to her daughter, Mary Holyoke Ward Nichols; given to her son, Andrew Nichols; given to seven of his grandchildren to own equally; David Wheatland (Topsfield, Massachusetts) purchased from Nathan P. Nichols (Hathorne, Massachusetts) January 16, 1975; donated to CHSI 1975.
Historical AttributesThis particular telescope belonged to and was used by Edward Holyoke (AB 1705, AM 1708), who made astronomical observations and prepared almanacs as Harvard librarian, tutor and fellow from 1709 onward. He became President of Harvard College in 1737 and served until his death in 1769.
Bausch, Lomb, Saegmuller Company
Date: 1905-1907
Accessories: screwdriver; key; dust cap; sunshade; carrying case; tripod (5162b)
Object number: 5162a
Alvan Clark and Sons
Date: 1910
Accessories: shipping crate, terrestrial eyepiece, dust cap, mount and tripod (2003-1-0077b)
Object number: 2003-1-0077a
C. L. Berger & Sons
Date: circa 1902
Accessories: pine case with lock (key not found); screwdriver; leather strap; sunshade; dust cover; tripod (see 5161b)
Object number: 5161a
Adie & Son
Date: circa 1850
Accessories: case; dust cap and sunshade; eyepiece
Object number: 5209
Jean-Baptiste-Charles Gonichon
Date: 1733-1763
Accessories: dust covers for tube and eyepiece
Object number: DW0814
Date: 1890-1930
Object number: RS0501