Description

MECHANICAL PARTS:

Lead screw dia.: 17 mm; Pitch: 1 mm; Threaded length: 200 mm

Lead screw and its nut are optically lapped to maintain constancy for the pitch.

Interferometer is provided by three scales.

Linear scale (0-150 mm graduated in mm) is attached with the left hand side of the bed of interferometer.

Graduated disc (0-100 div.) may be peeped through glass window provided with the head of the interferometer.  One division of graduated disc = 0.01 mm

A graduated slow-motion drum (graduation0-100 div.) is fitted on right hand side of the interferometer.  One division of slow-motion drum = 0.00001mm.

i.e. Least count of interferometer: 10-4 mm

OPTICAL PARTS:

Partially coated mirrors (2 Nos.) are heavily coated (metallic coating). Interference pattern formed by D1 & D2 lines of sodium are clearly visible even by naked eye. Mirrors are made of optical glass having step, i.e., one face is of dia. 23 mm (which is coated face); other face is 27mm and Thickness 12 mm. Surface figure of coated face: Better than l/10.Mirrors reflectivity: @ 80%. Coating material: Al. with protective coat of SiO2.

SPECIFICATIONS OF TELESCOPE:

Objective is an achromatic doublet of dia.25 mm and F.L.: 50 mm and Telescope magnification: 10x