Fine-adjustment screws used to precisely align the crosshairs onto a target after the main horizontal or vertical clamps have been locked.
To find the right guidance, you first need to identify your specific model. Most Hilger & Watts manuals cover these primary series:
Adjust the tripod legs until the circular bullseye bubble on the tribrach is perfectly centered. hilger watts theodolite manual
If the vertical circle does not read 90° when the telescope is horizontal, use the index adjustment screw [2].
Hilger & Watts produced several theodolite series, each with its own documentation. When searching for the right manual, it's very helpful to identify your specific model. If the vertical circle does not read 90°
Platforms like LandSurveyorsUnited often have members who can share PDFs of older manuals.
These glass circles are marked with degrees and minutes. 0° and 180°).
In many models, you will see two sides of the circle (e.g., 0° and 180°). A micrometer knob is used to align (coincide) the markings [2].
(Mainly No. 2 models) Used to align the graduation marks in the microscope to get the precise seconds reading.
Hilger & Watts Theodolite Manual: A Comprehensive Guide to Operation and Maintenance