Sector Lights, Continued
On either side of the line of demarcation between colored and white
sectors, there is always a small sector whose color is doubtful because
the edges of a sector cannot be cut off sharply. Under some
atmospheric conditions, a white light may have a reddish appearance.
Consequently, light sectors must not be relied upon entirely; but position
must be verified repeatedly by bearings taken on the light itself or by
other fixed objects.
When a light is cut off (obscured) by adjoining land, the arc of visibility
may vary with a ships distance away from the light. If the intervening
land is sloping, for example, the light may be visible over a wider arc
from a far off ship than from one close inshore.
Emergency lights of reduced intensity are displayed from many primary
lights when the main light is extinguished. These emergency lights may
or may not have the same characteristic as the main light. The
characteristic of the emergency lights are listed in column 8 of the Light
List. Again, refer to the example shown in figure 4-9 for Cape Henry
Light (LLNR 365).
A RACON is a radar beacon that produces a coded response, or radar
paint, when triggered by a radar signal. The coded response appears on
your radar screen as a series of dots and dashes. RACONs are placed
on important ATONs (buoys or structures) to assist in positive
identification of the aid. Column 8 of the Light List will describe the
RACON signal both as a Morse code letter and the equivalent dots and
dashes, for example RACON: X (-..-).