Classification System of the 19th Century
In the 19th century, astronomers grouped celestial objects into four primary categories:
Fixed Stars (Stellae Fixae)
Fixed stars, as the name implies, appeared as point-like light sources in the night sky. These were celestial objects that did not display any noticeable motion or changes in position. They served as a reference frame for astronomers and were believed to be relatively close to Earth. Their faint, unchanging appearance contributed to their classification as fixed stars.