it appeared that you weren't sure what angular size is. it is the apparent size of an object on the canvas around you. it's not limited to objects in the sky, though. professionally it's measured with a theodolite, but a telescope works well enough as an approximation.
it appeared that you weren't sure what angular size is. it is the apparent size of an object on the canvas around you. it's not limited to objects in the sky, though. professionally it's measured with a theodolite, but a telescope works well enough as an approximation.