2i2 Mr. Samuel Okell on a 



Description of a New Reflecting" Telescope and Ob- 

 servatory at Bowdon, Cheshire. By Samuel Okell, 

 F.R.A.S. 



{Received April 29th, 1890.) 



Mr. Calver, of Chelmsford, has recently completed for 

 me a new reflecting telescope of considerable dimensions. 

 This telescope is of the Newtonian form, in which, as is 

 now generally well known, the light is received on a mirror 

 or speculum, so figured as to bring objects to a focus 

 directly in front of itself. Near this focal point the image 

 is received on a smaller plane mirror placed at an angle of 

 45°, and by this it is again reflected to the eyepiece which 

 is fixed in the side of the upper portion of the main tube. 

 The large mirror in the present case is 20^ inches in 

 diameter and of 12 feet focal length, weighing nearly 

 ioolbs., and is a choice specimen of the skill of the maker. 

 Mr. Calver's abilities in the production of silvered glass 

 mirrors are already well known to astronomers. 



The mounting is equatoreal, of the German form, and is 

 very massive and complete, the whole weighing between 

 three and four tons. A concrete foundation some 8ft. below 

 the surface forms the base. Upon this, solid brickwork is 

 placed, containing a central chamber for the weights of the 

 driving clock, and this supports a stone slab 4ft. 6in. by 

 3ft. 6in., upon which the bed plate of the telescope rests. 

 The polar axis, 6in. diameter, and the declination axis, 4m. 

 diameter, both move with great ease on friction pulleys. 

 The tube, 22in. in internal diameter and 12ft. 6in. in length, 

 being iron, and owing to its size and considerable weight, is 

 provided with a novel mechanical appliance for bringing the 

 eyepiece to the most convenient position for observing, by 

 rotating in its cradle with worm and rackwork moved by a 

 hand wheel. The right ascension and declination circles 



