What are the objective and the eye-piece in an optical instrument?

(N/A) In optical instruments like microscopes and telescopes,the objective and eye-piece are the two primary lenses or lens systems.
$1$. Objective: This is the lens (or lens system) placed closest to the object being observed. It forms a real,inverted,and magnified image of the object at a position that serves as the object for the eye-piece.
$2$. Eye-piece (or Ocular): This is the lens (or lens system) placed closest to the observer's eye. It acts as a simple magnifier,taking the image formed by the objective and producing a final,virtual,and highly magnified image that the eye can view comfortably.