17th century Back Staff or Davis Quadrant – Holland, possibly England

17th century Back Staff or Davis Quadrant – Holland, possibly England

Stock Number: NM. 3-21

poa

In Holland the back staff was called an English quadrant and had no auxiliary scale. This instrument is probably Dutch, possibly early English.

Category: Navigational instruments

Description

After the astrolabe and the Jacob’s staff, in 1595 John Davis invented the back staff to determine the altitude of celestial bodies at sea. His improved design became known as the Davis Quadrant. The observer stood with his back to the sun and did not have to look at the bright sunlight. The back staff remained in use until the late 1700s when the octant and sextant became the new preferred tools over the back staff.
On the smallest circle segment of English specimens, an auxiliary scale is often provided for correction of the half of the diameter of the sun. In Holland the back staff was called an English quadrant and had no auxiliary scale. This instrument is probably Dutch, possibly early English.

 

The frame is made of rosewood, with ivory inlays, stars and fleur de lis. The arcs, the brace and vanes are of pear wood. The horizon vane is original, the eye and shadow vanes are of a later date, probably 18th century. The transversal vernier can be read accurate at two minutes.

 

Date: 17th century

WL: 36,5×63,5 cm   (14,3×25 in)

Signed: not signed

Origin: probably Netherlands, possibly England

Condition: in perfect condition, wear consistent with age and use

 

Curious about more? Then switch to http://archipel-maritime.nl/

Ask the Dealer

Item enquiry

To enquire about this item, complete the form bellow to send a message to the Dealer

Enter Email
Confirm Email
Sending

Dealer information

NL ARCHIPEL - International Maritime Galery

Archipel – International Maritime Galery in the Netherlands, sets itself to maritime objects of before 1900. The managing director worked as officer with the mercantile marine and the Royal Navy. As curator he was connected to one of the university museums in the Netherlands. As seaman and curator he has a lot of knowledge of naval history.

Shipping information
Payment methods