THE TERRESTRIAL TELESCOPE HAS ONE EXTRA LENS MORE THAN THE ASTRONOMICAL TELESCOPE. THE EXTRA LENS IS FOR

• A. improving the sharpness
• B. creating an inverted image
• C. magnification of the image
• D. erection of the image ✓

The answer to the question is: D. erection of the image

The terrestrial telescope has one extra lens more than the astronomical telescope, and this extra lens is for the erection of the image. The additional lens in a terrestrial telescope is called an erecting lens or an erecting prism. This lens or prism is used to correct the inverted image produced by the primary lenses of the telescope, thereby ensuring that the observer sees the objects in their correct orientation, i.e., upright and not inverted. This feature makes terrestrial telescopes suitable for viewing objects on Earth, such as landscapes, wildlife, and other terrestrial subjects.

Astronomical telescopes, on the other hand, do not require an erecting lens because they are designed for observing celestial objects such as stars, planets, and galaxies. These telescopes are optimized for providing a clear view of celestial bodies and do not need to correct the orientation of the image since there is no “up” or “down” in space.

In summary, the extra lens in a terrestrial telescope is for the erection of the image to ensure that terrestrial objects are viewed in their correct orientation.