2-foot Gregorian reflecting telescope
Date: 1750-1769
Inventory Number: DW0936
Classification: Telescope
Maker: Claude-Siméon Passemant (1702-1769)
Cultural Region:
Place of Origin:
Dimensions:
with barrel horizontal: 52 x 38 x 82 cm (20 1/2 x 14 15/16 x 32 5/16 in.)
barrel diameter: 10.6 cm (4 3/16 in.)
Accessories: dust cap
DescriptionThis brass Gregorian telescope is has its barrel covered in brown leather, which is stitched together. A knurled, brass focusing screw is attached near the tailpiece of the barrel on a diamond-shaped plate. The dust cap for the barrel has knurled edges and is pressure fit. The screw cap for the eye piece is missing.
The telescope has an aperture of about 4 inches and a focal length of about 24 inches.
The telescope has an altazimuth mount on top of a pedestal (decoratively turned), which rests on three, folding, cabriole legs.
The fine altitude adjustment is operated by an ivory-handled key with a steel post engaging with fine threads on the limb of a semicircle attached to the barrel by means of two arms secured by bolts with wing nuts The semicircle is pierced and engraved with two fanciful (sea) serpents. The coarse altitude adjustment is done by tipping the barrel after disengaging the key by means of an unusual brass lever pushing against a steel spring.
The fine azimuth adjustment is operated by another ivory-handled key with a threaded steel bolt going through the mounting assembly. The assembly terminates in a post that fits and turns inside a sleeve at the top of the stand. Coarse adjustment in azimuth is accomplished by turning the barrel after loosening a knurled thumb screw that pierces the sleeve.
The telescope has an aperture of about 4 inches and a focal length of about 24 inches.
The telescope has an altazimuth mount on top of a pedestal (decoratively turned), which rests on three, folding, cabriole legs.
The fine altitude adjustment is operated by an ivory-handled key with a steel post engaging with fine threads on the limb of a semicircle attached to the barrel by means of two arms secured by bolts with wing nuts The semicircle is pierced and engraved with two fanciful (sea) serpents. The coarse altitude adjustment is done by tipping the barrel after disengaging the key by means of an unusual brass lever pushing against a steel spring.
The fine azimuth adjustment is operated by another ivory-handled key with a threaded steel bolt going through the mounting assembly. The assembly terminates in a post that fits and turns inside a sleeve at the top of the stand. Coarse adjustment in azimuth is accomplished by turning the barrel after loosening a knurled thumb screw that pierces the sleeve.
Signedon tailpiece: Passemant Ingenieur / Du Roy au Louvre