Wherever a person finds himself as a result of an emergency, on land or in the ocean, in the jungle or in the desert, whether he decided to stay still or go on a trip, he must first orient himself, orient himself and determine his location.
Orientation by clock, sun and stars, determination of geographical longitude and latitude field conditions.
For the time being, orientation and determination of the cardinal points is not difficult, but in its absence one can resort to the help of the sun, stars, plants, etc. The direction to the north in the northern hemisphere is determined by turning the back to the sun at noon. The shadow cast back by the body, like an arrow, will point north.
Depending on the sign in front of the amendment, it is either subtracted or added. If the clock is set according to Eastern Standard Time, then it must first be converted to Greenwich, adding five hours. Then, adding (or subtracting) the correction, the result is converted into degrees.
An example of determining geographic longitude in the field.
On March 12, local noon came when the clock showed 14 hours 02 minutes, which in GMT, taking into account the belt correction (5 hours) and the correction of the equation of time (-10 minutes), will correspond to 18 hours 52 minutes (14 hours 02 minutes + 5 hours-10 minutes). The desired difference (18 hours 52 minutes – 12 hours) is 6 hours 52 minutes, which when converted to degrees corresponds to 103 degrees longitude, and longitude west, since local noon came later than Greenwich. This method allows you to determine the longitude of the place with an accuracy of 2 3 degrees.
Determination of geographical latitude in the field.
The geographical latitude of the place (between 60 ° north latitude and 60 ° south latitude) is calculated with an accuracy of half a degree (50 km) by the length of the day, i.e. time from the appearance of the solar disk over the horizon line until its complete disappearance. This method is especially convenient for determining latitude in the ocean in calm, calm weather. Only twice a year, from March 11 to 31 and from September 13 to October 2, when the day is approximately equal at all latitudes, this method is unsuitable.
Having determined the length of the day (the accuracy of the clock does not matter) using the nomogram (see figure), it is easy to establish the breadth of your location. To determine the northern latitudes it is necessary.
Measure the longitude of the day from the moment the top of the solar disk appears above the ocean horizon at sunrise until it disappears completely beyond the horizon at sunset.
Find the digit of the obtained longitude of the day on the left scale and connect it with the corresponding date on the right scale using a ruler or a stretched thread. At the intersection of the ruler or thread with the horizontal latitude scale is the desired latitude.
An example of determining geographic latitude in the field.
On August 20, the measured longitude of the day is 13 hours 54 minutes. Latitude by nomogram 45 ° 30&# 8242 ;. To determine the southern latitudes, you should: add 6 months to the corresponding date and determine the latitude using the new date, as described above.
May 11, the measured longitude of the day is 10 hours. 04 min Having added 6 months, we get November 11, the latitude according to the nomogram 41 ° 30&# 8242; Yu. w. When used, the nomogram should present a completely flat surface.
Local time based on compass and stars.
If the watch breaks or is lost, the local time is recognized with relative accuracy by the compass, measuring the azimuth in the sun. Dividing it then by 15 (the value of the rotation of the sun in one hour) and adding to the private unit, we get a number that will indicate local time at the time of counting.
The azimuth of the sun of 180 degrees will correspond to 13 hours local time (180: 15 + 1 = 13).
At night, you can use the stellar clock to determine. The dial for them is the sky with the North Star in the center, and with the arrow an imaginary line drawn to it through two stars of the Big Dipper bucket (see figure). If the sky is mentally divided into 12 equal parts, then each of them will correspond to a conditional hour.
To determine the time, the ordinal number of the month with tenths is added to the conditional hour (every three days they equal 0.1). The resulting amount is doubled, and then subtracted from a constant number of 55.3. In the case where the difference exceeds the number 24, it must also be taken away. The result of the calculation is local time..
On August 12, the hand showed 6 hours. Since August is the eighth month, and 12 days are 0.4, then 6 + 8.4 = 14.4; 14.4 x 2 = 28.8; 55.3 -28.8 = 26.5; 26.5 24 = 2.5. Thus, the local time is 2 hours 30 minutes at night.
Based on materials from the book Man in extreme environmental conditions.