Following these steps precisely—exactly as written in the Hilger Watts theodolite manual—can restore an instrument from being a paperweight to being accurate to within a few arc-seconds.
List of user-adjustable errors with step-by-step: hilger watts theodolite manual
Note: Factory-only adjustments (e.g., circle graduation errors) are clearly marked. Following these steps precisely—exactly as written in the
The crosshairs (reticle) can become misaligned due to transport vibration. The Hilger Watts theodolite manual provides screw locations and torque sequences to correct collimation errors. Guessing can shatter the delicate glass reticle. List of user-adjustable errors with step-by-step:
Curators will not lend the manual, but they will often email you a PDF of their reference copy for research purposes.
Because of British Commonwealth ties, many Hilger Watts instruments ended up in the Australian Army Survey Corps and the Canadian DOMS (Directorate of Military Survey). Search for "RAAF Hilger Watts manual" or "Canadian NRC Hilger Watts". The Australian War Memorial has digitized some training manuals that include operation sections for Watts theodolites.
Finding a physical or digital Hilger Watts theodolite manual today is a treasure hunt, but it is far from impossible. Here are the best strategies: