Astrolabe

Like the quadrant, the mariner's astrolabe was a simplified version of its astronomical counterpart and contained only a graduated scale and an alidade. To make it more effective for use at sea, its surface area was reduced by removing excess material at the center of the instrument and its weight was increased. The combined effect of these changes provided greater accuracy than the nautical quadrant making the mariner's astrolabe the preferred instrument among navigators for nearly three hundred years beginning around 1460 and continuing through 1700.

For more information, e-mail collections@MarinersMuseum.org.