Wndsn Telemeter Advanced Tutorials
Making the most out of our graphical distance computers.
Extend the measuring range, jump the scales to areas with higher precision marks, or use the Telemeter for triangulation; position determination without a compass, or with only one line of positioning.
Measuring Angular Size
The degree scale measures the angular size of the object observed, in other words the measured height in degrees, (easily converted to multiplication factors at the distance of 57.3 cm) which can be used when the actual height of the object is unknown.
Example: the full moon viewed from Earth has a diameter of about 0.5° (30 arc minutes) which, knowing neither distance nor actual diameter, doesn't tell us anything about its actual size compared to other objects such as the sun, which, at a much bigger diameter and distance, has about the same angular size when observed from Earth. Now, knowing either distance or actual diameter, the angular size can easily converted to the respective other, absolute value.
Also note that:
α = (S * 57.3) / D