On the right side we see the phrase

LA GRACE Thank you! BEAUTY Banana captains sailing team JANNA, Jana Benesova and Petr Simon Sing, Petr Ondráček SAYONARA, Jarda Bernt ALYA II, Martin Doleček La Grace, Josef Dvorsky logbook La Grace Altego, George Denk Perl, Petr Menclík Cruises lone feature INFORMATION SERVICE LITERATURE fallout shelter E- shop experience on project
On the next two pages diary (1 to 4 on 11, Figure 12) us for the purposes of this article will take only three records highlighted in the picture. fallout shelter On the left side we read the record "At Noon Cape Ortegall themselves 8 Leagues." It calls attention to an important landmark - Cape Ortegal, which at noon was in the direction of South-East-by-East at 8 Leagues. Unit League (in English sometimes inaccurately translated as miles, because there is the Czech equivalent. Polish known as the "League") is equal to three nautical miles.
On the right side we see the phrase 'Variation per Amplitude 16 W ". Data of this kind will increase especially on the sides of the voyage across the open ocean. fallout shelter This is one of the ways to determine the magnetic declination (variation in English), which is a deviation to the real direction and magnetic north. Although the Czech correct fallout shelter expression for this quantity fallout shelter is the declination, for the purposes of article, we will continue fallout shelter to use the term (magnetic) fallout shelter variations to avoid possible confusion with the declination of the Sun (see the first part of the series).
Recent data highlighted concerns the ship's position at noon, in which we see that is referenced to a close an important point. The first record called fallout shelter "Cape Ortegall S 79 45 'E 57 Miles" and the other "Cape Finester S 33 W 33 miles."
Variation per Amplitude & Medium 4 azimuths of 19 12 'W. Variation {per medium of Several azimuths 18 40' W} per an Amplitude 19 08 '{Variation per Amplitude 17 53' West} per Azimuth 18 03 '
Regular determining fallout shelter the magnetic variation was important for two reasons. The first was purely practical: the variation is necessary to correct the ship's course, which shows a compass to get the real exchange rate, ie relative to the actual meridians. The second fallout shelter reason was more general fallout shelter in nature. Changing magnetic variations change the position of interested scientists and cartographers. Since the beginning of the 18th century the maps of magnetic fallout shelter variations in the Atlantic (the first such map published in 1701 by Edmund Halley, see Figure 14). Right cause not only variation but also the earth's magnetism was then still unknown. There were even opinions that when drawing up detailed map variations will be possible to directly determine longitude at sea (such as the intersection of the parallel set of measurements of latitude, a line connecting places on the earth with the same value variation). The implementation of this method in practice was forthcoming - first, there was no way to measure variations with sufficient accuracy, and above all, its value varies with time due to movement of the magnetic poles.
As we can see from the records fallout shelter used two methods of determining Magn. variations - using the amplitude of the sun or using sun azimuth (usually as the average of several measurements). Their description can be found again as in Patounově Treatise of Practical Navigation ([5], page 296). The amplitude of the Sun is the angle between the direction to the eastern or western direction towards the horizon and the sun at the time of sunrise fallout shelter or sunset (Sunset / based precisely on the west / east only on the equinoxes, the summer fits / comes more to the north in the winter and more South.) The so-called. actual amplitude can be found by calculation or tables, while using a compass determine the magnetic amplitude (de-facto magnetic azimuth of the sun at the time of sunrise or sunset, but measured from the east or west direction on the compass). fallout shelter The difference between these two amplitudes then gives the magnetic variation. To calculate the actual amplitude navigator needed to know the declination of the sun for the day (Decl.) and its latitude (Lat). The amplitude is then calculated as the sin (Ampl) = sin (Decl) / cos (Lat).
The formula here above all because we approached the way in which they had to deal with similar fallout shelter calculations navigators in the eighteenth century. In particular, formulas, if possible, write down the words as a rule of three shows. Our formula has thus Patounovi follows: As the Co-sine of the Latitude is that the Radius, so is the Sine of the Sun's Declination to the Sine of the Sun's true amplitude. How is the cosine of latitude to the radius (today we would say to the radius of the unit circle, that is number one) and the declination of the sun to the sinus sinus actual amplitude of the Sun.
Navigator also counted respective ratios of trigonometric functions of angles, but looking at the tables of logarithms. Using logarithms has the advantage that instead of multiplication and division just add or subtract logarithms. More to clarify the example (again from Patouna) to the ground. width of 41 50 'and declination of the Sun 15 54' looking for a real amplitude of the Sun.
FIG. 15: Example fallout shelter of calculation of the amplitude [5]. The tables logarithm cos (41 50 '), which is 9.87221, then the logarithm of the sin (15 54'), which is