Longines Lindbergh Angle Horaire Mode D'emploi page 9

A The dial display is designed to simultaneously show time (hours, min-
utes and seconds) and longitude (degrees and minutes of arc).
B The mobile inner dial shows the seconds. It can be rotated by means
of the crown, for synchronisation with the radio time signal.
C The rotating bezel permits correction for the equation of time (which
varies from day to day).
A space-time dial, and how it works
The design of the Lindbergh Hour Angle Watch is based on the fact that
the rotation of the earth is 360° in 24 hours, 180° in 12 hours, 15° in one
hour, and 15' arc in one minute. Thus:
The hour hand shows 15° per hour. One turn of the dial (12 hours)
represents 180°.
The minute hand shows 1° in 4 minutes or 15° per hour. The 15° are
subdivided into units of 15 minutes arc, engraved into the mobile bezel.
One rotation of the sweep seconds hand is equivalent to 15' arc. The
mobile inner dial is divided into 60 seconds and 15 minutes arc.
Synchronizing with radio time signal
Pull out the crown to the intermediate position (2) and rotate the inner
dial so that the sweep seconds hand coincides with the 60/15 mark at
the last tone of the time signal.
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Crown has 3 positions
1. Normal position
Crown is in winding position: Your natural wrist movements auto-
matically wind the watch until it stores a 42-hour power reserve. Manual
winding is needed only when you have not worn your watch for some
days.
2. Intermediate position
Crown rotates the inner dial in either direction.
3. Fully pulled out
For stopping seconds hand and time-setting: Fully pull out crown
(3); the seconds hand stops.
Set watch by turning the crown in the desired direction.
Push back crown to normal position (1) at telephone, radio or TV time
signal.
Pushpiece at 4 o'clock
Releases the case back so that the movement becomes visible through
a protective watch glass.
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