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Geochron Boardroom Model in Cherry finish (79,294 bytes) Please read Principles of the Sun Earth Relationship As Demonstrated by Geochron. This is an illustrated discussion of the Analemma, and Equation of Time, and how they and other aspects of the relationship are presented by Geochron.

WHAT MAKES A GEOCHRON TICK? Whether it's the Original Kilburg, the Standard, an Executive model or one of the Boardroom models, every single Geochron made is hand-crafted in Redwood City, California, USA. Each gear is individually hand-cut to ensure optimum synchronization. The Geochron's map has been reproduced in part from Chronaflex positives of the U.S. Naval Oceanographic Office, and this is printed on dimensionally stable Mylar using special specially formulated inks designed to make the map resistant to ultraviolet light. The map is on an endless belt driven slowly from left to right using a precision electric clock motor that is synchronous with the Earth's rotation. These maps are periodically revised and sold by us as a retrofit kit for those who wish to update their own Geochron.

Right: Geochron Boardroom Model in Cherry wood, custom finished to match customers wood sample (90,430 bytes).

Note this Geochron shows noon just at the east tip of the Australian Longitude in December. It is easy to see why
the days are shorter in the North while longer in the South Hemisphere at this time of year.
Click on image to see enlarged view (330,971 bytes).

And by the time each Geochron is hand-crated for shipment anywhere, it has been personally inspected passing through 24 designated key inspection points. After more than thirty years, every single Geochron is still made completely by hand to your specifications. If you require a little more technical information, here are some other things to know about the Geochron.

Geochron Boardroom Model flush mounted (51,282 bytes) Mounting The Geochron can be mounted onto any flat surface in the same manner as a picture. Standard surface mounting brackets are supplied. A Display Stand is also an available option. If you prefer, the Geochron can also be recessed into a wall with special Flush Mount Brackets that may be ordered separately but are included as standard equipment with Boardroom Model. The recess opening required for a Flush Mount is 33-5/8" (854.1mm) x 21-3/8" (543mm) x 4" (101.6mm). Installation instructions are supplied with each unit.

Right: Geochron Boardroom Model in Cherry wood, custom finished flush mounted by customer (51,282 bytes).
Click on image to see enlarged view (201,944 bytes).

To view Geochron illustrated installation instructions:

  • Geochron Flush Mounting Illustrated instructions about how to install the Geochron recessed into a wall with the Flush Mount hardware.

  • Geochron Surface Mounting Illustrated instructions about how to install the Geochron onto a wall or stand with its provided Wall Bracket hardware.

Manual Controls The Geochron has three simple control knobs. Two are located at the base of the unit and are used primarily for the initial setting. Another moves the map horizontally to set time and day of the week. It is also used to determine time of sunrise, sunset and the number of daylight hours at any location at a time other than current. The other knob sets the date indicator and light pattern. A third knob controls the minute dial located at the Geochron's upper right hand corner.

Finish The Geochron comes in the customers choice of either: laminate finish, Princess Plonge leather, custom wood housings, or metal covering. Each finish can be made with various accent moldings. Other custom finishes are available at additional cost. Finish samples are available upon request. The Boardroom Model features a limited edition plaque with gold anodized trim.

To view Geochron cabinet finish choices:

Electrical Geochron is supplied with your choice of standard currents, including 120 and 220 volt, 50 and 60 cycle, etc.

Geochron fluorescent bulb end (13,539 bytes) Illumination Each Geochron uses two easily replaceable F15T8D, 15 watt fluorescent tubes. These are daylight balanced lights with two prongs (G13 Bi-Pin) at each end, 18 inches long. An electric switch at the base turns the lights on or off without disturbing the timing mechanism; this makes it practical to keep a Geochron in any room (or one in every room!), since the light can be easily turned off to sleep, for privacy, etc. Flush mounted units can be pulled gently by the bottom of the frame to access this switch.

Right: One end of a Geochron fluorescent bulb showing its dual prongs (13,539 bytes).

The bulbs are conservatively rated for 5,000 hours of continuous use. But note Company Seven has maintained a Geochron on display in our Laurel, MD showroom for years and never replaced either fluorescent tube, starter or ballast. The fluorescent tubes, starters and ballasts used in its internal illumination are easily accessed for service or replacement without dismantling the unit.

Protective Glass A brilliant glass pane shields the facing side of the mylar world map. This is easy to clean if needed.

Credits. The Geochron world map is reproduced in part from Chronaflex positives of the U.S. Naval Oceanographic Chart #1262.

Legal time zone information is based on data from the U.S. Department of Defense Mapping, Time Zone Chart #76. Delineation of the time zones and designs of the time scale are original with Geochron and are copyrighted by Geochron Enterprises, 1986.

    US Trademark Registration No. 1,495,046 GEOCHRON.
    US Trademark Registration Logo No. 1,516,324. US Patent Nos. 3,316,706 and 3,226,926.


Geochron's map moves imperceptibly from left to right while its time scale atop the map stands still. The time scale can be shifted manually, or on Model B visually, for a distance equal to one hour. To the left of "noon" on the scale is A.M., to the right, P.M. On the left and right of the map are black vertical lines which represent the circumference of the earth or 24 hours.

Time zones are identified by letters. The bold purple lines represent time zone boundaries. Horizontal distances on the map are related to time on the basis of one inch to the hour.

ZONE TIME in the land areas within time zone boundaries is indicated by pointers bridging the zone at the top of the map and the stationary time scale. These are calibrated in 5 minute increments.

When a time zone extends vertically to the top of the map without being blocked off by a boundary line, its associated pointer indicates the time for that zone. (Example: Zone W)

Where a time zone is blocked off and does not extend vertically to the top of the map, applicable time is indicated by reference to the pointer identified with the same letter as that placed within the boundaries of the zone. (Example: Finland, Zone B.)

Countries and zones in which time differs by a fraction of an hour are identified by a letter plus numerals. Applicable time is indicated on the time scale by the pointer identified with the same letter, to which is added the number of minutes indicated by the numeral. (Example: India, E + 30.)

DAYLIGHT SAVINGS TIME Shift the time scale manually (or visually) to the left a distance equal to one hour and read time same as zone time.

LOCAL TIME Project a perpendicular line or meridian from any locale on the map to the time scale. The point at which the line intersects the time scale indicates local time.

APPARENT SOLAR TIME for any meridian is obtained by subtracting from, or adding to local time, the number of minutes indicated by the horizontal distance between the center of the black dot (Sun) to the left or right of the mean noon line. One inch is equivalent to one hour.

EQUATION OF TIME is indicated by the horizontal distance of the black dot (sun) the mean noon line translated into time on the basis of one inch to the hour.

DAY OF THE WEEK The prevailing day of week in any part of the world is self-evident. For example, if London appears on the right of the Date Line on Geochron's map, the "day of week" shown on the right applies. If it appears on the left side of the Date Line, the "day of week" shown on the left applies.

DATE The Calendar moves imperceptibly from East to West (relative to map). There are two indicator lines, one each associated with the wording "Right of Date Line," "Left of Date Line." Indicators show the prevailing date on either side of the Date Line.

SUN The Black Dot indicates "apparent noon" position of the sun. "Mean noon" is shown by the red line running vertically from the time scales's 12:00 o'clock (noon) line. The dot moves according to declination and meridian passage of the Sun. A figure 8 pattern results from this gradual shift of the sun's zenith position. It is called "Analemma." If the dot is left of the red line, the sun's meridian passage occurs before 12:00 o'clock noon. if it is to the right, it occurs after 12:00 o'clock noon. The distance from the dot to the line can be translated into time on the basis of one inch to the hour. Thus, we have "equation of time." The Black Dot's position North or South of the Equator indicates the "Sun's Declination."

SUNRISE AND SUNSET Geochron's illuminated pattern shows in what parts of the world the sun is shining and where it is dark. The terminators, or the demarcation between light and dark is the moment of sunrise on the left and the moment of sunset on the right. The configuration of this demarcation is changing continually as sunrise and sunset changes daily throughout the world. A vertical line from the intersection of the demarcation and a location on the map to the time scale above will provide quick reading of sunrise and sunset "local time." However, when zone time is desired, move the map placing the location over the sunrise or sunset demarcation; then read the time indicated by the arrow of the related time zone. Obviously, the duration of daylight is readily determined by the difference between the time of sunrise and sunset for any locale.

For a complete list of service centers, view

Warranty Company Seven will inspect each unit delivered through our showroom to as another quality control measure. The Geochron is warranted against defective workmanship and materials for a period of one year from date of purchase. Geochron components supplied by manufacturers other than Geochron Enterprises carry the warranties of these other manufacturers. Company Seven will back the warranty and remain available to service or support any instrument sold by Company Seven.

FREE ART PIECE, AND CONVERSATION PIECE WITH EVERY PURCHASE When you purchase a Geochron you're buying much more than a timepiece. You will be the owner of what the Smithsonian Institute calls "the last significant contribution in time keeping. You will be the owner of a unique piece of art that, unlike most art pieces, actually has a function. (Since when did the Mona Lisa do anything but smile?) And lastly, you will also be the owner of quite a conversation piece, Which just might explain why Geochrons have adorned the homes and offices of celebrities and dignitaries including: John Lennon, General Norman Schwarzkopf, Shirley Temple Black, Ronald Reagan.

So there you have it. Of course, there is plenty more we could tell about the Geochron Global Time Indicator. But by now we expect you have all the facts needed to make an intelligent purchase decision.

We hope you now understand why Geochron is without a doubt, the premier world timepiece for anyone whose personal or professional interests lie beyond the boundaries of local time zones. However, should need additional information or have any questions then please visit our showroom, or contact Company Seven for advice, or just call 301-953-2000 during regular business hours. We'll be glad to explain anything, or to demonstrate the Geochron in our showroom.


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