Maker

Zeiss, Oberkochen, Germany

Model

P9

Serial Number

n/a

Dimensions

37 mm diameter, 92 mm high

Image

Description

This double pentaprism (optical square) allows to set out right angles, to determine a point on a line and to drop a perpendicular from a point onto a line. Points are usually marked by (red-and-white) ranging poles.

The instrument at hand has a window at the top that directs the view to theright, a window at the bottom showing the view to the left and a narrow horizontal window at half height giving the view straight ahead.

Below the optical part is a cylindrical tube that permits to hold the device or to mount it on a plumbing pole. The plumbing rod, when suspended by two fingers, makes the device vertical.

This particular device has reflective surfaces at the top and bottom surfaces of the two pentaprisms and a viewing aperture in the handle, thus permitting steep sights to the left and right. A cut at the bottom of the handle allows to attach a plumbob. The bore of the handle has a diameter of 10 mm.

History & comments

after 1974

Conservation

in (non-standard) leather pouch marked "DCL Surveying Instruments, 54 High Street, Sydney"

Condition

excellent

Remarks

Dates

Catalogued on 9 October 2014 by JMR. Photo by JMR.