This device demonstrates how a telescope takes images. A convex objective lens at the front focuses light and forms an image of a distant object at the focal point. In real photography, a camera sensor is placed at this position to capture images of celestial objects.

Step 1: Observe the position of the target and adjust the altitude and azimuth to aim the telescope at the target on the wall.
Step 2: Look at the white screen at the focal point behind the telescope to see whether an image appears, and move the screen forward or backward until the image becomes clear.