Among the features of the Theta that were noted by Matys and Mrazek was that the Theta could be oriented north-south then vertically leveled with a bubble, which results in alignment with accuracy better than ±0.5°. Matys and Mrazek then overlaid the resulting image with parallel lines representing different heights, and azimuth labels. With the overlay, it is possible to determine the height of the horizon. Practical applications of Matys and Mrazek’s method include being able to evaluate an observing site’s horizon for obstructions such as mountains, etc. that would prevent observation of a passing celestial object. This method can also be used to determine the amount of light pollution at a site.
Matys and Mrazek’s paper can be accessed here.