"Apogalacticon" is a word that is rarely used in everyday communication, and it may be challenging to find synonyms that could replace this word. Some synonyms that could convey similar meanings include "outer space museum," "astronomical observatory," and "astronomy center." These words imply a place where people can learn about space and celestial objects. Alternatively, the words "apogee" and "galacticon" are two parts that make up the word "apogalacticon," and these two parts could be used separately as synonyms. "Apogee" refers to the point where an object is farthest from the Earth, while "galacticon" implies a gathering of enthusiasts interested in galaxies and space exploration.