Surveying Instrument Collection
Maker |
CARL ZEISS, Oberkochen, Germany |
Model |
5 mm Plane Parallel Plate Micrometer for Zeiss Ni2 Level |
Serial Number |
n/a |
Dimensions |
75 x 86 x 165 mm |
Image |
|
Description |
This PPP micrometer attaches to the telescope of the Zeiss Ni2 automatic level. It allows to move the line of sight 2.5 mm up and down. The device is used in precise levelling with invar line staffs graduated at 5 mm intervals. The range of the micrometer is 11 units (1 unit = 0.5 mm). The micrometer is graduated in steps of 0.5 units on the metal readout scale. Interpolation to 0.05 units (±0.025 mm) is possible. The invar staffs for this PPM must be graduated and numbered in 0.5 cm steps. In precise levelling, the staffs are read directly to the half-centimetre (since each half-centimetre line carries a number) and the decimals of the staff interval (5 mm) on the micrometer drum. The booking and the computations are carried out in terms of the (1/2 cm) staff graduation intervals. The final levelled height differences are obtained by division by 2. The double run levelling precision of the Zeiss Ni2 with plane parallel plate micrometer and invar staffs is quoted as ±0.3 mm * SQRT(km). Order Number 704402 Weight: 0.9 kg |
History & comments |
Device is post 1950. |
Conservation |
In leather tubular container |
Condition |
PPPM and container in excellent condition |
Remarks |
Box marked Fa67, P/C(plat card) 7336 Micrometer engraved "ZEISS West Germany" |
Dates |
Catalogued in 2012 by JMR. Photo by JMR. |