| slovo | definícia |
Sidereal clock
(gcide) | Sidereal \Si*de"re*al\, a. [L. sidereus, from sidus, sideris, a
constellation, a star. Cf. Sideral, Consider, Desire.]
1. Relating to the stars; starry; astral; as, sidereal
astronomy.
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2. (Astron.) Measuring by the apparent motion of the stars;
designated, marked out, or accompanied, by a return to the
same position in respect to the stars; as, the sidereal
revolution of a planet; a sidereal day.
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Sidereal clock, day, month, year. See under Clock,
Day, etc.
Sideral time, time as reckoned by sideral days, or, taking
the sidereal day as the unit, the time elapsed since a
transit of the vernal equinox, reckoned in parts of a
sidereal day. This is, strictly, apparent sidereal time,
mean sidereal time being reckoned from the transit, not of
the true, but of the mean, equinoctial point.
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Sidereal clock
(gcide) | Clock \Clock\ (kl[o^]k), n. [AS. clucge bell; akin to D. klok
clock, bell, G. glocke, Dan. klokke, Sw. klocka, Icel. klukka
bell, LL. clocca, cloca (whence F. cloche); al perh. of
Celtic origin; cf. Ir. & Gael. clog bell, clock, W. cloch
bell. Cf. Cloak.]
1. A machine for measuring time, indicating the hour and
other divisions; in ordinary mechanical clocks for
domestic or office use the time is indicated on a
typically circular face or dial plate containing two
hands, pointing to numbers engraved on the periphery of
the face, thus showing the hours and minutes. The works of
a mechanical clock are moved by a weight or a spring, and
it is often so constructed as to tell the hour by the
stroke of a hammer on a bell. In electrical or electronic
clocks, the time may be indicated, as on a mechanical
clock, by hands, but may also be indicated by direct
digital readout, with the hours and minutes in normal
Arabic numerals. The readout using hands is often called
analog to distinguish it from the digital readout. Some
clocks also indicate the seconds. Clocks are not adapted,
like the watch, to be carried on the person. Specialized
clocks, such as atomic clocks, may be constructed on
different principles, and may have a very high precision
for use in scientific observations.
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2. A watch, esp. one that strikes. [Obs.] --Walton.
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3. The striking of a clock. [Obs.] --Dryden.
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4. A figure or figured work on the ankle or side of a
stocking. --Swift.
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Note: The phrases what o'clock? it is nine o'clock, etc., are
contracted from what of the clock? it is nine of the
clock, etc.
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Alarm clock. See under Alarm.
Astronomical clock.
(a) A clock of superior construction, with a compensating
pendulum, etc., to measure time with great accuracy,
for use in astronomical observatories; -- called a
regulator when used by watchmakers as a standard for
regulating timepieces.
(b) A clock with mechanism for indicating certain
astronomical phenomena, as the phases of the moon,
position of the sun in the ecliptic, equation of time,
etc.
Electric clock.
(a) A clock moved or regulated by electricity or
electro-magnetism.
(b) A clock connected with an electro-magnetic recording
apparatus.
Ship's clock (Naut.), a clock arranged to strike from one
to eight strokes, at half hourly intervals, marking the
divisions of the ship's watches.
Sidereal clock, an astronomical clock regulated to keep
sidereal time.
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