Final answer:
The Fernbank Observatory houses the largest Cassegrain reflector telescope in the southeastern United States, which is a type of reflecting telescope that uses a concave primary mirror and a secondary mirror to direct light through a hole in the primary mirror to the eyepiece.
Step-by-step explanation:
The telescope housed in the Fernbank Observatory, which is the largest in the southeastern United States, is a Cassegrain reflector. Reflecting telescopes like the Cassegrain design utilize a concave primary mirror and a secondary mirror to focus light. The light is then directed through a hole in the primary mirror, where it is brought to a focus at the eyepiece or a detector for observation or imaging. The Cassegrain reflector, chosen for most large professional astronomical research telescopes, is preferred over Newtonian and refracting telescopes for its compact design and the avoidance of chromatic aberration.