Angular Width Equations
The following equations allow the calculation of the (visual and actual) width w of a far away object (either flat or spherical) whose distance d and angular width θ are known.
It is possible to find the (visual and actual) width of an object whose distance d and angular width θ are known. If the object is a disc or (is drawn on) a flat surface, the equations will use the (arc)tangent; if spherical or cylindrical, the (arc)sine.