alb3813317

Davis' Quadrant

Share
Pinterest
Twitter
Facebook
Copy link
Email

Add to another lightbox

Do you already have an account? Sign in

You do not have an account? Register

Buy this image. Select the use:

Title: Davis' Quadrant

Caption: The backstaff is a navigational instrument that was used to measure the altitude of a celestial body, in particular the sun or moon. When observing the sun, users kept the sun to their back and observed the shadow cast by the upper vane on a horizon vane. It was invented by the English navigator John Davis who described it in his book Seaman's Secrets in 1594. The quadrant was the earliest astronomical instrument converted for nautical use. It was used to determine the altitude of the Polestar or sun and, concurrently, the location of the ship in degrees of latitude.

Personalities: JOHN DAVIS

Category: Science: History

Credit: Album / Science Source / New York Public Library

Releases: ? Model Release: No - ? Property Release: No
Rights questions?

Image size: 4800 × 3283 px | 45.1 MB

Print size: 40.6 × 27.8 cm | 1889.8 × 1292.5 in (300 dpi)

Keywords: ALTITUDE • APPARATUS • ART • ARTWORK • BACKSTAFF • CELEBRITIES • CELEBRITY • DAVIS QUADRANT • DAVIS' QUADRANT • DEVICE • DIAGRAM • DRAWING • FAMOUS PEOPLE • FAMOUS • HISTORIC • HISTORICAL • HISTORY • ILLUSTRATION • ILLUSTRATIONS • ILUSTRATION • IMPORTANT • INSTRUMENT • JOHN DAVIS • MARITIME • MEASUREMENT • MEASURING • NAUTICAL • NAVIGATION • NAVIGATIONAL • NAVIGATORS • NOTABLE • QUADRANT • SCIENCE • SCIENCE: HISTORY • SEAMEN'S SECRETS • TOOL • WELL-KNOWN