Which symbol represents a celestial fix in navigation?

In navigation, a celestial fix is represented by a specific symbol that indicates the position determined using celestial bodies, such as stars or planets. The empty circle symbolizes this celestial fix because it effectively conveys the idea of a point in space where the navigator has determined their position based on observed celestial objects. This form of representation is widely recognized in nautical charts and navigation tools, providing an intuitive way for navigators to understand and communicate their position resulting from celestial observations.

The other options represent different concepts in navigation: the open triangle is often used for a radar fix, the empty square may represent a position obtained from dead reckoning, and the filled circle typically indicates a fix obtained from GPS or other electronic means. Understanding these symbols is crucial for effective navigation, as they help mariners quickly understand the type of fix or method used to determine their location at sea.