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An instrument used to register the time of an event or graphically record time intervals such as the duration of an event.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



an instrument for precise registration of the time at which an event occurs. Chronographs are classified by the method of registration used as pen recorders, printers, and photographic instruments.

In a pen recorder chronograph, the instant at which the event occurs is recorded by several specially constructed pens on a uniformly moving paper tape. Each pen has an electromagnetic system that holds the pen in one of two stable positions. The changeover of positions occurs when a current is fed to or disconnected from the electromagnet; at this instant the trace of the pen on the tape will show a break. One pen is usually controlled by the reference clock, and the other pens are controlled by the test instruments, such as other clocks, contact micrometers of transit instruments, and relays that are controlled by accurate radio time signals. Measurements of the coordinates of the break points in the trace are used to calculate the instants of time according to the reference clock system. Several other designs of pen recorder chronographs have been used in astronomy, in which plotting or perforating needles or electric sparks are substituted for pens. Pen recorder chronographs have an accuracy of approximately 0.01 second. They became obsolete by the mid-20th century.

In a printing chronograph, numerals are printed on a paper tape at the instant when a current is fed to or disconnected from the control circuit of the electromagnet. The numerals correspond to the instant of time with respect to some conventional time scale that the chronograph produces with its own quartz oscillator. A printing chronograph has three cylindrical disks of equal diameters, with raised graduation marks on the outside surfaces. The first and the second disks have 60 graduation marks each, and the third disk has 100 marks; the graduation marks are numbered from zero to 59 and from zero to 99, respectively. The first disk makes one revolution per hour and registers minutes; the second disk makes one revolution per minute and registers seconds; and the third disk makes one revolution per second and registers tenths, hundredths, and thousandths of a second. At the instant when the electromagnet is activated, a paper tape and an inked tape are both very briefly pressed against the rotating disks, and impressions of the numerals, graduated marks, and reference index are printed on the paper. The disks are driven at a uniform speed by a synchronous motor fed by a quartz oscillator. Modern printing chronographs register time with a precision of approximately ±0.005 second.

Photochronographs use disks of practically the same type as those in printing chronographs. The disks and the reference index are photographed at the instant a flash lamp is fired. The reference signal and the test signal are fed to the control circuit of the flash lamp. The difference of the two readings can be seen on the developed photographic film and is used to define the instant of the appearance of the test signal with respect to the time system of the reference clock. Photochronographs are practically inertia-free instruments because there are no mechanical components in the recording units. They are therefore used where the precision of printing chronographs proves inadequate. Photochronographs register time with an error no greater than ±0.001 second. Chronographs are used primarily in astronomy.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Vilkul demonstrates how the chronographic borrowings from the NIml are mixed in origin; they come both from the Chronograph of the Great Description (Khronograf po velikomu izlozheniiu, hereafter HVT) type and directly from the Slavonic Hamartolos and Malalas.
Her book provides a coherent and logical explanation for the history of both the chronicle and the chronographic traditions of medieval Rus'.
74, is cautionary, repudiating the numismatic practice of using coins as chronographic pinpoints.
Alcmaeon's date is itself a matter of some controversy, but there is no real reason to doubt Aristotle's testimony that he was active during the old age of Pythagoras.(28) The chronographic tradition identifies Py- thagoras' floruit with the rise to power of Polycrates around 530 B.C.;(29) this is probably not far from the truth and would suggest a floruit for Alcmaeon somewhere in the last quarter of the sixth century.
2W, as argued above - something impossible under the traditional chronographic reckoning of Semonides' date.(50) And we can meet the one serious objection to Semonidean authorship put forward by modern critics: the feeling that its vocabulary is closer to that of the late sixth or even the fifth century.
The chronographic tradition dates Phocylides of Miletus contemporary with Theognis, giving his floruit as 544-541 B.C.(52) This synchronistic dating is itself open to suspicion on grounds similar to those we have advanced for doubting the synchronism of Semonides and Archilochus.
While none of the arguments I have presented in the last four sections is by itself definitive, I believe that the cumulative effect of all these considerations, taken together with those of sections 1 and 2, is to suggest that there is a serious case for rejecting the traditional date our chronographic sources assign Semonides and instead seeing him as a poet of the late sixth century, coeval with Xenophanes and Heraclitus.
Since Pausanias seems to have known from his chronographic source that the reigns of Archelaos and Charillos coincided, Charillos would be the appropriate Eurypontid king.(30) the invasion of the Argolid under Nicander (3.7.4) is problematic.
For these prehistoric sections then, there is nothing that cannot be attributed to the chronographic source or Herodotus.
Any extra detail supplied was either Pausanias' own, or that of his chronographic source.
26 The possibility, at least, must remain that this detail occurred in Pausanias' chronographic source, with its interest in aetiology.
Mesopotamian Chronicles is not only a useful volume for Assyriologists, but for other scholars in the social sciences or humanities who need up-to-date, reliable, and readable English translations of these fifty-three chronographic texts.