Copper gold-plated reflecting telescope

[Copper gold-plated reflecting telescope]

Copper gold-plated reflecting telescope, made in London, England, in the 18th century, has a length of 74 cm, a cylinder diameter of 11 cm, an objective diameter of 10 cm, an eyepiece diameter of 2 cm, and an eyepiece aperture of 0.3 cm. The old collection of the Qing Palace
The object mirror is coated with aluminum (or some kind of metal). This kind of telescope has no chromatic aberration and is suitable for the wide spectral area from ultraviolet to infrared, but its field of view is small. A copper gold-plated triangular bracket is attached under the lens barrel, with a height of 45 cm and a rotation of 180 °. The left side of the lens barrel is attached with a 31.5cm long and 2cm diameter star guide mirror, which is a small visual telescope attached to the telescope. Its optical axis is parallel to the optical axis of the main telescope. The eyepiece has a high magnification, a large field of view, and it is easy to find the observation object. Especially, there is a cross hair at its focal plane, which can be used to aim at the star to monitor whether the telescope accurately tracks the observed object
This kind of reflecting telescope is called Gregory telescope, which is made by Gregory according to the principle of Newton’s reflecting telescope. The primary mirror is a rotating paraboloid, and the secondary mirror is a concave rotating ellipsoid. The secondary mirror is located behind the focus of the primary mirror. After the light is reflected by the secondary mirror, it passes through the circular hole in the primary mirror and forms a positive image at the end of the lens barrel. Engrave the English word “DYEFINCH COMHILL LONDON” on the bobbin of the eyepiece tube.

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