Question

For a telescope, the object's visual angle is measured from its own position, which is effectively:

Options

• At the objective's focal point

• At the eyepiece's focal point

• The least distance of distinct vision

• At infinity

Answer 1

Objects seen through a telescope cannot be brought to the least distance of distinct vision from the objective in the way they can be in microscopes. For telescopes, the object's visual angle is measured from its own position, which is effectively at infinity.