Which term is not a recognized navigation light term in the material?

Which term is not a recognized navigation light term in the material?

• A. Occulting
• B. Isophase
• C. Flashing
• D. Isopter

Answer: (D)

Navigation light patterns are described by standardized terms that tell you how long the light stays on and how it pulses. The three familiar terms you’ll encounter describe common patterns: occulting, isophase, and flashing. Occulting means the light is on for a longer portion of the cycle than it is off, with brief interruptions. Isophase describes equal durations of light and darkness, giving a steady rhythm. Flashing denotes a quick, brief flash followed by a longer dark interval. Isopter, however, is not a recognized term used to describe navigation light patterns in the material, so it isn’t used to characterize a light’s behavior. Knowing these terms helps you interpret lights on vessels and aids to navigation correctly.

Navigation light patterns are described by standardized terms that tell you how long the light stays on and how it pulses. The three familiar terms you’ll encounter describe common patterns: occulting, isophase, and flashing. Occulting means the light is on for a longer portion of the cycle than it is off, with brief interruptions. Isophase describes equal durations of light and darkness, giving a steady rhythm. Flashing denotes a quick, brief flash followed by a longer dark interval. Isopter, however, is not a recognized term used to describe navigation light patterns in the material, so it isn’t used to characterize a light’s behavior. Knowing these terms helps you interpret lights on vessels and aids to navigation correctly.