Sextant - 1673 - 纪限仪

The sextant is used to measure the angle of elevation of a celestial object above the horizon. It is used to calculate the angle between two objects, although it is limited to 60 degrees of arc. In navigation, it is used to to take a measure of the angle of the sun at noon to determine latitude. This is one of the instruments designed by Ferdinand Verbiest.

Last update: May 2007
© Marilyn Shea, 2007