Telescope and Theodolite - Indian Laws - General

Telescope and Theodolite The Shorter Oxford English Dictionary, Third Edition, at page 2255, gives the meaning of the expression Telescope , and it reads as under: Telescope (te-liskop) sb. 1648-(It, telescopio (Galilei) or mod. L. telescopium (Porta); see Tele-Scope). An optical instrument for making distant objects appear nearer and larger, consisting of one or more tubes with an arrangement of lenses, or of one or more mirrors and lenses, by which the rays of light are collected and brought to a focus and the resulting image magnified. Telescopes are of two kinds: refracting, in which the image is reproduced by a lens (the object-glass) and reflecting, in which it is produced by a mirror or speculum; being magnified in each case by a lens or combination of lenses (the eye-piece). The smaller hand-telescopes are always refracting, and consist of two or more tubes made to slide one within another for convenience of packing into a narrow compass and for adjusting the lenses as required for focussing the image, b. Astr. A constellation south of Sagittarius 1891. (b) It also gives the meaning of theodolite , at page 2279, as below: Theodolite (pi-o-doleit). 1571. [First in mod.L. form theodelitus (Leonard or Thomas Digges, its probable inventor); of unkn. origin] A portable surveying instrument, orig. for measuring horizontal angles, and consisting essentially of a planisphere or horizontal graduated circular plate, with an alided or index bearing sights; subsequently variously elaborated with a telescope instead of sights, a compass, level, vernier, micrometer, and other accessories, and now often with the addition of a vertical circle or arc for the measurement of angles of altitude or depression. Hence theodolitic a. of, pertaining to, done, or made with a. t. The New Encyclopaedia Britannica , Volume 18, 15th Edition, at page 97, gives the meaning of telescope , as below: A telescope is an instrument used to view distant objects. The word is derived from the Greek tele, far and skopein, to see . Modern telescopes are of two types, optical and radio. In optical telescopes light is collected and focussed so that it can be magnified and either examined through an eye piece or photographed. The light may also be directed into an auxiliary device, such as a spectrograph (see also optics, principles of; optical engineering). A radio telescope may consist of a single wire, a pattern of wires, a spherical or parabolic dish, or a number of dishes arranged in a pattern. Very sensitive electronic detectors and amplifiers have been developed for radio telescopes, which are usually much larger and more complex than optical telescopes. In one such telescope, the longbaseline radio interferometer, the two elements may be separated by hundreds or even thousands of miles. The New Encyclopaedia Britannica , Volume 17, 15th Edition, gives the meaning of theodolite , at page 830, under the heading Angle-measuring equipment , and it reads, as under: Angle-measuring equipment . The theodolite is the basic instrument for measuring horizontal and vertical angles. It consists essentially of a sighting tube in the form of a telescope, and horizontal and vertical scales so set up that horizontal and vertical angles of the object sighted in the telescope can be read from the scales. The New Lexicon Webster s Dictionary of the English Language, 1991 Edition, at page 1017, gives the meaning of the telescope and it reads as below: tel-e-scope (teliskoup) 1. n. an optical device that focuses light (objective) from distant objects so that the image formed may be observed (eyepice). Telescopes are usually tubular in form and vary in size from easily portable to very large instruments mounted so that they can be focused and turned on several axes by means of electric motors and fine gears. They are classified according to function. It also gives the meaning theodolite at page 1025, as below: The-odo-lite (Oi-od-lait) n. an instrument used by surveyors to measure vertical and horizontal angles, consisting of a small telescope moving along a graduated scale. (origin unknown). Bureau of Indian Standards issued specifications as respects vernier theodolite. The foreword to the specifications so issued reads as under: Foreword-This Indian Standard (First Revision) was adopted by the Bureau of Indian Standards, after the draft finalised by the Optical and Mathematical Instruments Sectional Committee had been approved by the Light Mechanical Engineering Division Council. Theodolite is an instrument for precise measurement of horizontal and vertical angles. The vernier theodolite is provided with graduated horizontal and vertical circles and two small vernier scales. The vernier scales are movable and remain in sliding contact with the graduated circles. The vernier theodolite is not so precise as other advanced designs, such as optical theodolite but is still used largely due to lower cost and simplicity of design. Vernier theodolite may be used for all types of surveys required for small and large scale mapping. This standard is one of a series of Indian Standards dealing with surveying instruments. A separate Indian Standard has also been prepared to cover the requirements of optical theodolites (IS 2976: 1964 Optical theodolite ). LAWRENCE AND MAYO INDIA (PRIVATE) LTD. VERSUS STATE OF TAMIL NADU - 1997 (12) TMI 610 - MADRAS HIGH COURT