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Light Sector Settings
The light sector setting in a Garmin chartplotter enables the device to display a ring around a navigation light. The circle indicates how bright the light is from the light beacon. The larger the circle around the light beacon, the brighter the light. The ring does not tell how far away from the light beacon the light is visible—many factors such as ambient brightness, clarity, fog affect the visibility.
GPSMAP® chartplotters1 | ECHOMAP™ UHD2 chartplotters | ECHOMAP™ Ultra 2 chartplotters
From the navigation chart select 
> Layers > Chart > Navaid > Light Sectors make selection On, Off or Auto1
From the navigation chart
The light sector setting options:
Off - This setting will not display the ring around the navigation light
On - This setting will display the ring around the navigation light at all times
Auto - This setting will turn the ring on or off depending on the zoom scale the map is being viewed at
1 For legacy chartplotters please see the owner's manual for directions