Example: Circle shows 45°; micrometer reads 12' 30" → .
Online communities such as The Surveying Forum or specific vintage machinery groups on Facebook and Reddit are excellent resources. Members frequently share digitized manual copies or provide step-by-step troubleshooting for specific model variations.
: Specifically designed for tracking weather balloons, these featured unique hand-cranked micrometer drums and a closed-frame design to withstand harsh environments.
Extend the tripod legs firmly into the ground, ensuring the tripod head is visually level.
Adjust the focus until the ground mark and the internal reticle crosshairs are both sharp. hilger watts theodolite manual
When looking through the small reading eyepiece, you will typically see two illuminated windows labeled (Vertical) and H (Horizontal).
Use the coarse sighting aids (peep sights) on top of the telescope to roughly align the instrument. Tighten the horizontal and vertical clamps, then use the slow-motion tangent screws to center the target exactly on the crosshairs.
Rotate the upper instrument body (alidade) until the long plate bubble level is parallel to any two of the three leveling footscrews.
A massive, heavy instrument made before the Hilger merger. Manuals for these are rare and written in a very formal, engineering-heavy style. Example: Circle shows 45°; micrometer reads 12' 30" →
Turn the main internal focusing knob until the target is clear. Move your eye slightly up and down; if the crosshairs appear to shift against the target, eliminate this parallax error by fine-tuning the focusing knob.
Single-reading system (views one side of the circle at a time).
Finding an original can be difficult. However, several resources exist:
A step-by-step guide is given in the 1986 training film: "Setting up a theodolite -- Measuring horizontal angles -- Measuring vertical angles -- Packing up". : Specifically designed for tracking weather balloons, these
When it comes to the history of surveying, photogrammetry, and precision engineering, the name stands as a beacon of craftsmanship. Formed in 1948 through the merger of two prominent British optical and scientific instrument companies, Hilger & Watts produced some of the most reliable and highly regarded mechanical theodolites of the 20th century.
Reading a Hilger & Watts glass circle requires understanding how the internal optical prisms project the scales into the auxiliary eyepiece. Reading the Microptic No. 1 Scale
Integrated into the alidade or the tribrach base to allow precise centering over a ground station mark without the use of a traditional plumb bob.
Websites like the Land Surveying History archives, The Virtual Museum of Surveying , and various university civil engineering departments frequently host free, downloadable PDF scans of original E.R. Watts and Hilger & Watts instruction booklets.
Institutions such as the Smithsonian have digitized catalogs and related documentation regarding Hilger & Watts 1950s instruments.
Use the legs of the tripod to place the optical plummet roughly over the ground point.