You could use a surveying device such as a theodolite , moving around in the room, measuring angles to the bulb from different positions, and using trigonometry to work out the distance.
He set up his theodolite to get the bearings for the sundial and indicated its orientation on a north-south line.
By the 1970s, however, the electronic theodolite began to replace the transit since it could measure angles more accurately on both the horizontal and vertical axes.
They retrieved all but one of 700 parts and so meticulous was their work - the position of each was plotted with a theodolite and recorded - that even now they could still all be taken back to the exact points where they were found.
A bunch of men was clustered around a surveyor's theodolite .
Tracked by theodolite , these balloons indicated the speed and direction of the wind in the upper atmosphere.
Then there were his surveying tools: theodolite , plane table, brass scales, parallel ruler.
Near it stands a theodolite , similar to one Morgan used.
Technological advances included a marked wheel for measuring distances accurately, a greatly improved theodolite , and the gradual elimination of picturesque but irrelevant detail.
Any number of homemade traps and snares were primed at any one time, carefully crafted in his toolshed with top-quality materials, and placed with due care by spirit level and theodolite in the garden for maximum bloodletting.