Here are a few examples that show how a sextant can be used to find location ... This means that if the sun is above the longitude of 0 degrees at noon, one hour later it will be above 15 ...

Here’s an example: Last January 9, at 02:30 Universal Time, I assumed that I was at latitude N50° and longitude 30°53.9’W. With my sextant, I measured the altitude of the star Sirius to be ...

Sextants use a similar premise to astrolabes ... Navigators based their longitude on their speed, how long they had been ...