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| Man’s Natural Timepiece |
| From the first crude sundials that divided the days
into vague and irregular intervals, to the finest navigational
chronometers that maintain split-second accuracy over
long periods, our basic source of time has always been
the rotation of the earth we live on and the apparent
motion of the sun that this rotation causes. Even before
any concept of time existed, the daily alternation of
light and darkness must have regulated man’s activities,
as it does the activities of animals today. As recently
as one hundred thirty years ago, every city, town and
hamlet on earth observed its own local time based on
the instant that the sun reached its zenith at that locality,
and "high noon" was the universal time for setting clocks
and watches. |
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| The Time Zone Problem |
| Those simple and straightforward days of Local Sun
Time ended when the first transcontinental railroads
ushered in the era of modern long-distance transportation.
The time confusion for travellers and trainmen became
so great on long trips that in the 1870s the 24 "standard" world
time zones we know today were set up by international
agreement. These zones solved one problem but created
another. Today, in our age of high speed jet ravel, electronic
communications, and growing international involvement,
more and more people need to know, or are interested
in knowing, what time it is somewhere else — often halfway
around the earth. The problem that time zones created
is that the ordinary clock and watch are highly inadequate
for telling time on a global basis. |
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| The Inadequacy Of
The Clock |
| Conventional clocks are essentially local time indicators
and no more. (The last basic innovation in the design
of clocks — outside of improved accuracy and minor gimmickry — was
back in the 17th century when someone added the minute
hand to the theretofore single-handed clock dial.) Because
clocks and watches present time as an abstract (and sometimes
meaningless) number, learning the time in another part
of the world is a matter of working with other abstract
numbers (time zone conversion factors) as well as figuring
out whether it is A.M. or P.M., what day of the week
and what date it is. Since there are at least 34 local
world time zones (24 standard and 10 nonstandard) the
problem is not simple. And, for this same reason, the
idea of multiple dials or clocks for keeping track of
world time is impractical. |
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| Geochron: The New
World Timepiece |
Geochron solves all these problems in one stroke
by combining the answers to the two questions "What
time?" and "Where?" in a single easy-to-read graphic
analog. Physically, Geochron looks like a framed world
map, about 3 by 2 feet in size. It is designed to be
hung on the wall. The colorful map itself, a precision
Mercator projection printed on dimensionally stable
Mylar, is an endless belt that is driven slowly from
left to right by an electric clock motor in synchronization
with the rotation of the earth. All known legal time
zone boundaries are delineated on the map which, in
most cases, converge on lettered pointers on the top
edge of the map. These letters identify the standard
time zones and also represent the short-wave radio prefix
for that zone.
Specifically, the Geochron displays the following:
- Legal Zone Time
- Greenwich Mean and Apparent Times
- Local Apparent Time
- Moments of Sunrise and Sunset
- Duration of Daylight
- Sun's Meridian Passage
- Sun's Equation of Time
- Degrees of Latitude and Longitude
- The Geographic Extent of the Prevailing Day and
Date
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| Reading World Time
On Geochron |
| The time zone arrows point to a stationary time scale
across the top of the map that reads from midnight to
the left, through noon in the middle, to midnight again
at the right. To read the time in any standard zone in
the world, you simply find that place on the map and follow
the zone boundaries to the arrow which points out the
correct time. Certain nonstandard and pocketed zones have
boundaries that do not extend to an arrow. These are marked
with a letter and a number. The letter tells you which
arrow to read and the number shows the deviation from
standard time. In the case of India, for example, the
designation is E + 30. This means that you add 30 minutes
to time you read on the E pointer. Simple addition of
a fraction of an hour in the case of the 10 nonstandard
zones is the only calculation ever required in reading
the Geochron. |
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| Reading The Date And Day Of The Week On
Geochron |
| Since the map is moving slowly across the frame from
left to right, the International Dateline crosses the
frame once each day. The days of the week observed on
either side of the Dateline are displayed in windows near
the bottom of the map. The date and month for these two
days are likewise shown on an indicator mounted at the
bottom of the Geochron. |
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| Geochron: Graphic Analog Of Day And Night |
| Perhaps the most fascinating thing about Geochron is
that it shows the exact portions of the earth that are
in daylight, and those that are in darkness, at the moment
you are observing Geochron. The brightly illuminated pattern
in the center of the map delineates those areas that are
in daylight. The left edge of this pattern is the line
of sunrise as it sweeps across the earth, and the right
edge is the line of sunset. Because the length of the
day changes daily as the earth progresses through its
seasons, the light pattern on Geochron changes also, almost
imperceptibly, from day to day. Thus, with Geochron you
can read the time of sunrise and sunset and the relative
length of day and night for any latitude. Because Geochron
is a graphic analog, the viewer soon gains an instinctive
appreciation of what time it is everywhere and it no longer
becomes necessary to read an abstract number to know if
it is an appropriate time to call someone in Paris, France,
or Sydney, Australia. A glance at the light pattern on
the map instantly tells you whether it is daylight at
those places or the middle of the night. This illuminated
pattern also shows the progress of the seasons during
the year. Such heretofore abstract phenomena as the summer
and winter solstices and the vernal and autumnal equinoxes
are clearly and graphically shown by the Geochron light
pattern. |
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| Other Uses For Geochron |
| Geochron has two simple controls that allow it to be
used for far more than just telling time. One knob at
the base of the unit allows the map to move the map horizontally
across the frame. It is used to set the correct time on
the Geochron scale when it is first plugged in. But, by
moving the map, you can also determine the time of sunrise
and sunset at any locality on that day and see the relative
effect of latitude on these times. The second knob at
the base of the unit allows you to set the date indicator
to any day of any month in the year. Since the light pattern
mechanism is coupled to the date indicator, this also
changes and shows the light condition on earth at that
time of year. This feature has been found valuable by
educators, motion picture producers, military men, as
well as by the average person who just wants some help
in planning his vacation. Geochron also shows the exact
zenith position of the sun at any time on any date and
graphically indicates the relationship between Apparent
Solar Time and Mean Solar Time as expressed in the Equation
of time. This is indicated by a small black dot that follows
the zenith position of the sun as it traverses the earth. |
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