Vanes for Back Staff or Davis Quadrant
One or more vanes of most back staffs have disappeared. These four vanes are an opportunity to complete a back staff. They are new made by hand from old pear wood. It are exact copies of the vanes of the John Dupee Back Staff of 1764 of the Kelton Collection. Also the lens in the shadow vane is special made with the required power of 4 dioptres and a focal length of 20 centimeters.
The vanes are delivered on order. They are adapted in color and thickness of the scales to the back staff for which they are intended. References available on request.
Photo 1 and 2 show the front and back of the new vanes.
Photo 3 to 8 show the new vanes on the left and the old on the right.
Photo 9 shows the new blind vane.
On image 10 the Dupee backstaff, see also NM.4-46.