[gdszxaad] Sextant

The sextant is a neat instrument, able to very precisely remotely and passively measure properties of distant objects.

In this age of GPS where knowing one's location is easy, perhaps reverse the classical use of the sextant to use it to measure the sizes of things, e.g., the height of a building.

Does a camera accomplish the same thing?  One would need a calibrated camera to derive angular separation from pixel separation in an image.  And it fails for scenes wider than the camera's field of view, though pasting images into panoramas could mitigate that.

Inspired by quadrant, octant, sextant.