The ACCUTRON Astronaut timepiece is primarily designed for the airline pilot and marine navigator and provides for a simultaneous display of local time and Greenwich Mean Time.
It can also be used to advantage by the globetrotter and international businessman to indicate both local time and a second time zone.
In addition to the conventional 12-hour dial, with hour, minute, and sweep second hands, the ACCUTRON Astronaut timepiece is provided with a revolving rim, calibrated into 24 hours and a special G.M.T. hand which revolves around the dial once every 24 hours. This enables the owner to adjust the setting of his timepiece to any two time zones throughout the world.
Setting To Local Time
When setting to local time make sure that G.M.T. hand (triangular tip) is on correct side of dial. This hand should be on right side of dial if the time is a.m. and on left side if p.m. At midnight, this hand and regular hour hand both point to 12 marker on the conventional dial.
The ACCUTRON timepiece, unlike conventional watches, has a unique free-floating gear train. For this reason, the following procedure is required to set the hands exactly to the second:
1. Lift setting handle (Pic. 1) when sweep second hand is exactly at 60 second marker (Pic. 2). All hands will stop instantly.
2. Turn hands in either direction until regular hour and minute hands indicate desired time. In doing this, advance minute hand slightly ahead of desired minute marker and then turn it back to this marker. At this point sweep-second hand may have advanced several seconds. Proceed as if hand had not moved.
3. Turn setting handle slightly forward, making certain not to turn it far enough to move minute hand. (This is to permit setting handle to return to flat position without causing hands to jump.)
4. When sweep-second hand or audible signal of time standard by which you are setting your timepiece reaches the 60th second, snap the setting handle back to normal position.
Setting To A Second Time Zone
1. Establish time differential between zone you are in and other time zone in which you are interested.
2. Turn rotatable ring until hour for other time zone which corresponds to midnight local time is opposite the 12 marker on the conventional dial.
G.M.T. hand will now indicate on outer ring the correct hour in other time zone. (Pic 3)
For example, your timepiece shows 4 P.M. Eastern Standard Time and you want your 2nd time zone at Greenwich Mean Time which is 5 hours later. At midnight local time, Greenwich Mean Time would be 5 A.M. or 0500 hours. Rotate the outer rim until the 5 marker on the rim is opposite the 12 marker on the inside dial. The G.M.T. hand will now point to 2100 hours on the 24-hour rim dial, the correct Greenwich Mean Time.
The minute and sweep-second hands apply to both time zones alike.