sextant I have is divided into 2 equal pieces (unlike the one in the picture). The left one is just glass (so that we can see the horizon directly through the telescope), whereas the right one is a proper glass that reflects the light from the sun and the index mirror. The index bar is movable, so the index mirror can also move and the image on the right part of the horizon mirror moves relatively to its left part by the number of degrees on the measure. To find the altitude of the sun, the person taking the measurements must alight the horizon with the lower border of the sun. The same method applies when you want to find the altitude of Polaris, Moon or any other celestial body. Now, it is time to take my own measurements in order to find my longitude and latitude. Firstly, I need to know what time is it in the place where I currently am. Easy? Not quite… The official time, used by the countries (on the TV, radio and all your clocks) is different from the solar time determined by the position of the sun (unless you are in the middle of the time zone given for a particular country). Figure 2: Using a sextant [13] Find your coordinates!
A good example is the place where I am writing this article – Lublin in the eastern Poland (Figure 3). The time zone border (22° 30’ meridian) goes directly through the city. Being in its eastern part, we can experience a time schizophrenia. Why? Suppose it is noon official time in early March (so there is no DST yet). You can see noon on your watch, but the sun has already been in its highest point (i.e. it is 12.30 solar time). Moreover,
Figure 3: Solar time vs. official time in Poland. [14]
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