heliograph


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heliograph

(hē`lēəgrăf) [Gr.,=sun-writer], signaling device using flashes of sunlight. It has two mirrors that are used to reflect sunlight on a distant point and a shutter through which the sunlight passes so that messages may be transmitted in telegraphic code by means of long and short flashes. It was used in ancient times and as recently as the 19th cent. by the U.S. army in the SW United States and by the British army in India.
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Heliograph

 

(1) In meteorology, an instrument for automatically registering the duration of sunshine, that is, the time when the sun is above the horizon and not covered by clouds. There are many types of heliographs. The most widespread in the USSR is the Campbell-Stokes heliograph, in which a stationary sphere serves as a lens that gathers the rays of the sun onto a cardboard strip marked off by hour lines. The strip is burned through by the sun’s rays if irradiation exceeds 0.3 to 0.4 calories per sq cm per min. Because of the apparent daily motion of the sun, the burn is in the form of a line, the length of which serves to measure the duration of the sunshine. A continuously registering actinograph can also function as a heliograph.

REFERENCE

Sternzat, M. S. Meteorologicheskie pribory i nabliudeniia. Leningrad, 1968. Page 209.
(2) In astronomy, a telescope adapted for photographing the sun. It is used to obtain photographs of all or part of the solar disk in a wide range of wave lengths. A heliograph can be used in combination with a coelostat. Because of the tremendous illumination generated by the sun, the aperture ratio of the heliograph objective can be minimal. In order to obtain pictures of the sun with large linear dimensions, as large a focal length is chosen for the heliograph as possible. At the same time, so as not to increase the size of the instrument, additional magnification systems are used. The heliograph is equipped with a fast-action shutter (usually of the curtain type), giving exposure times of from 0.02 to 0.001 seconds. One of the first heliographs was installed by the Russian astrophysicist M. M. Gusev at Wilno (Vilnius) in 1854.
(3) In military affairs in the 19th and early 20th centuries, a light-signaling device for transmitting messages (by Morse code) with a mirror used to reflect light rays. The heliograph is effective over distances of 18 to 40 km in daytime and 3 to 8 km at night.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

heliograph

[′hē·lē·ə‚graf]
(communications)
An instrument for sending telegraphic messages by reflecting the sun's rays from a mirror.
(engineering)
An instrument that records the duration of sunshine and gives a qualitative measure of its amount by action of sun's rays on blueprint paper.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

heliograph

1. an instrument with mirrors and a shutter used for sending messages in Morse code by reflecting the sun's rays
2. a device used to photograph the sun
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
Following the purchase, Heliograph now owns a total of 765.310 shares, corresponding to 42,02% of the total share capital and voting rights in Glunz & Jensen.
Caption: Figure 9: Heliograph of the correlations between Maximum Diastolic Blood Pressure of the day and the statistically significant different CPT-induced EEG oscillations depicted by concentric circles in the (-1)-(0)-(+1) continuum.
Consenquently, the algorithms fail to recover fine solar structure when used to heliograph imaging.
This will enable the new "Luscher Technologies Ltd" to take advantage of all kinds of synergies in the area of administration, logistics and operations using the infrastructure and support of Daetwyler Graphics AG (a subsidiary of Heliograph Group).
Sir Henry Christopher Mance invented a form Quiz of the Day ANSWERS: 1 Madrid; 2 Cold Feet; 3 The Mance heliograph; 4 Sweetest Thing; 5 Ullapool; 6 Octant; 7 Sloane Ranger; 8 Catatonia; 9 Basketball; 10 Sir James Goldsmith.
He survived and walked through the desert to find help, finding shelter in an abandoned German reconnaissance truck and constructing a heliograph to find rescue.
In 1873 the Signal Corps heard of the success the British had with the heliograph, a device which used mirrors to reflect sunlight and could be manipulated to make a flashing signal.
Within one hundred and fifty years after Joseph Niepce produced his first heliograph and thus launched the age of photography, photographic imagery was to become linked with twentieth century computer technology.
(In England, the word was first presented in a lecture at the Royal Society, eventually winning out over its contemporary rivals photogene and heliograph.) The philosopher Geoffrey Batchen remarks that the combination of photos, light--which is purely nature, the sun, God--and graphein, writing--which is purely human, purely constructed, pure artifice--is paradoxical: he calls it an "impossible binary opposition."
(15) Joseph Nicephore Niepce, 'Memoire on the Heliograph', in Alan Trachtenberg (ed.), Classic Essays on Photography (New Haven, 1980), p.
From Kitchener's headquarters orders were flashed by telegraph and heliograph links across the veldt to a total of fifteen columns to intercept, contain and trap the rampaging Boers.
The heliograph would revolutionise battlefield signalling two decades later, but at the time of the Crimean War orders from distant commanders were often based on out-of-date or erroneous information: senior officers were expected to exercise wide discretion before obeying such orders.