In relation to ATONs, what does the term ‘fixed light’ refer to?

The term 'fixed light' in relation to Aids to Navigation (ATONs) refers to a light that is continuously illuminated during specific hours, typically from dusk to dawn. This consistent illumination provides mariners with reliable visual guidance during nighttime or low visibility conditions, such as fog or heavy rain. A fixed light does not flash; instead, it remains on steadily to mark a particular location or hazard, ensuring that it is easily recognizable at any moment within its operational hours.

In this context, the options that suggest alternative behaviors—like only being on during the day or being always off—do not align with the definition of a fixed light. Similarly, a light that flashes periodically would instead be classified as a flashing light, which serves a different purpose in navigation by attracting attention or indicating specific conditions, such as a navigation hazard. Understanding these distinctions is crucial for safe navigation and effective use of ATONs while on the water.