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[wikipe] Wikipedia The Free Encyclopedia Search [ ] Search * Create account * Log in [ ] Personal tools * Create account * Log in Pages for logged out editors learn more * Contributions * Talk Contents move to sidebar hide * (Top) * 1Abbreviations * 2Light patterns Toggle Light patterns subsection + 2.1Fixed light + 2.2Flashing light + 2.3Occulting light + 2.4Isophase light + 2.5Quick light + 2.6Morse code + 2.7Fixed and flashing + 2.8Alternating * 3Class of light * 4See also * 5Notes * 6References * 7External links [ ] Toggle the table of contents Light characteristic [ ] 15 languages * Catala * Cestina * Dansk * Deutsch * Espanol * Francais * `bryt * k`art`uli * Nederlands * Ri Ben Yu * Norsk bokmal * Polski * Portugues * Svenska * aithy Edit links * Article * Talk [ ] English * Read * Edit * View history [ ] Tools Tools move to sidebar hide Actions * Read * Edit * View history General * What links here * Related changes * Upload file * Special pages * Permanent link * Page information * Cite this page * Get shortened URL * Download QR code * Wikidata item Print/export * Download as PDF * Printable version In other projects * Wikimedia Commons From Wikipedia, the free encyclopedia Description of navigational light [400px-Light_characteristics]Symbols and abbreviations for light characteristics [220px-Fl]Florauden seamark in Norway and its light characteristics A light characteristic is all of the properties that make a particular navigational light identifiable. Graphical and textual descriptions of navigational light sequences and colours are displayed on nautical charts and in Light Lists with the chart symbol for a lighthouse, lightvessel, buoy or sea mark with a light on it. Different lights use different colours, frequencies and light patterns, so mariners can identify which light they are seeing.^[1] Abbreviations[edit] While light characteristics can be described in prose, e.g. "Flashing white every three seconds", lists of lights and navigation chart annotations use abbreviations. The abbreviation notation is slightly different from one light list to another, with dots added or removed, but it usually follows a pattern similar to the following (see the chart to the right for examples). * An abbreviation of the type of light, e.g. "Fl." for flashing, "F." for fixed. * The color of the light, e.g. "W" for white, "G" for green, "R" for red, "Y" for yellow, "Bu" for blue. If no color is given, a white light is generally implied. * The cycle period, e.g. "10s" for ten seconds. * Additional parameters are sometimes added: + The height of the light above the chart datum for height (usually based on high water). e.g. 15m for 15 metres. + The range in which the light is visible, e.g. "10M" for 10 nautical miles. An example of a complete light characteristic is "Gp Oc(3) W 10s 15m 10M". This indicates that the light is a group occulting light in which a group of three eclipses repeat every 10 seconds; the light is white; the light is 15 metres above the chart datum and the nominal range is 10 nautical miles. Light patterns[edit] Fixed light[edit] A fixed light, abbreviated "F", is a continuous and steady light. Flashing light[edit] "Flashing light" redirects here. For other uses, see Flashing Lights (disambiguation). A flashing light is a rhythmic light in which the total duration of the light in each period is clearly shorter than the total duration of the darkness and in which the flashes of light are all of equal duration. It is most commonly used for a single-flashing light which exhibits only single flashes which are repeated at regular intervals, in which case it is abbreviated simply as "Fl". It can also be used with a group of flashes which are regularly repeated, in which case the abbreviation is "Fl(2)" or "Gr Fl(2)", for a group of two flashes. Another possibility is a composite group, in which successive groups in the period have different numbers of flashes, e.g. "Fl. (2+1)" indicates a group of two flashes, followed by one flash. A specific case sometimes used^[2] is when the flashes are longer than two seconds. Such a light is sometimes denoted "long flashing" with the abbreviation "L.Fl". If the frequency of flashes is high (more than 30^[3] or 50^[2] per minute) the light is denoted as a "quick light", see below. Occulting light[edit] [170px-Coquet_Island_Lig]Clockwork occulting mechanism formerly in use at Coquet Island Lighthouse. An occulting light is a rhythmic light in which the duration of light in each period is longer than the total duration of darkness. In other words, it is the opposite to a flashing light where the total duration of darkness is longer than the duration of light. It has the appearance of flashing off, rather than flashing on. Like a flashing light, it can be used for a single occulting light that exhibits only a single period of darkness or the periods of darkness can be grouped and repeated at regular intervals (abbreviated "Oc"), a group (Oc(3)) or a composite group (Oc(2+1)). The term occulting is used because originally the effect was obtained by a mechanism (e.g. a vertical or rotating shutter) periodically shading the light from view. Isophase light[edit] An isophase light, abbreviated "Iso", is a light which has dark and light periods of equal length. The prefix derives from the Greek iso- meaning "same". Quick light[edit] A quick light, abbreviated "Q", is a special case of a flashing light with a high frequency (more than 30^[3] or 50^[2] per minute). If the sequence of flashes is interrupted by regularly repeated eclipses of constant and long duration, the light is denoted "interrupted quick", abbreviated "I.Q". Group notation similar to flashing and occulting lights is also sometimes^[2] used, e.g. Q(9). Another distinction sometimes^[2] made is between quick (more than 50 and less than 80 flashes per minute), very quick (more than 80 and less than 160 flashes per minutes, abbreviated "V.Q") and ultra quick (no less than 160 flashes per minute, abbreviate "U.Q"). This can be combined with notations for interruptions, e.g. I.U.Q for interrupted ultra quick, or grouping, e.g. V.Q(9) for a very quick group of nine flashes. Quick characteristics can also be followed by other characteristics, e.g. VQ(6) LFl for a very quick group of six flashes, followed by a long flash. Morse code[edit] A Morse code light is light in which appearances of light of two clearly different durations (dots and dashes) are grouped to represent a character or characters in the Morse Code. For example, "Mo(A)" is a light in which in each period light is shown for a short period (dot) followed by a long period (dash), the Morse Code for "A". Fixed and flashing[edit] A fixed and flashing light, abbreviated "F. Fl", is a light in which a fixed low intensity light is combined with a flashing high intensity light. Alternating[edit] An alternating light, abbreviated "Al", is a light which shows alternating colors. For example, "Al WG" shows white and green lights alternately. Class of light[edit] Table I Class of Feature Abbr. Definition Example Representation Light 1. Fixed F A continuous, F R # steady, light. 2. Occulting The total duration of light in each period is greater than the total duration of darkness and the dark intervals (occultations) usually have the same duration. 2.1 A dark period is Single-occulting Oc repeated Oc R 6s # regularly. A group of dark 2.2 Oc(x) periods are Oc(2) G # Group-occulting repeated 8s regularly. Light similar to group-occulting, except that successive 2.3 Composite Oc groups in the Oc(2+3) # group-occulting (x+y) same period W 18s contain different numbers of dark periods. The duration of 3. Isophase Iso the light and Iso R # dark periods are 4s equal. 4. Flashing The total duration of light in each period is less than the total duration of the dark and light appearances (flashes) usually have the same duration. A flash is 4.1 repeated Single-flashing Fl regularly at a Fl G 5s # rate below 50 per minute. A light flash, duration of more 4.2 L.Fl than 2 seconds L.Fl W # Long-flashing (long flash) is 10s repeated regularly. A group of a 4.3 specific number Fl(3) R Group-flashing Fl(x) of flashes are 15s # repeated regularly. Similar to 4.4 Composite Fl group-flashing, Fl(2+1) group-flashing (x+y) but with several W 15s # groups of flashes. 5. Quick flashes are at a frequency of between 50 and 79 flashes per minute. 5.1 Continuous Quick flashes quick Q are repeated Q W # regularly. Groups of a given number of Q(3) G 5.2 Group quick Q(x) quick flashes 9s # are repeated regularly. The sequence of flashes is 5.3 Interrupted regularly I.Q R quick I.Q interrupted by 14s # dark intervals of constant duration. 6. Very quick Flashes are repeated at a frequency between 80 and 159 flashes per minute. Very quick 6.1 Continuous VQ flashes are VQ W # very quick repeated regularly. Groups of a given number of 6.2 Group very VQ(x) very quick VQ(3) G # quick flashes are 4s repeated regularly. The sequence of flashes is 6.3 Interrupted regularly I.VQ R very quick I.VQ interrupted by 9s # dark intervals of constant duration. 7. Ultra quick The flashes are repeated at a frequency equal to or greater than 160 flashes per minute. Ultra quick 7.1 Continuous UQ flashes are UQ W # ultra quick repeated regularly. The sequence of ultra quick flashes is 7.2 Interrupted I.UQ regularly I.UQ R # ultra quick interrupted by 6s dark intervals of constant duration. The flashes have markedly different 8. Morse code durations and Mo(K) G Mo(x) are grouped 6s # together to form one or more characters in Morse code. A light that combines a fixed light with a light flashing 9. Fixed and flashing with a stronger F.Fl Y F.Fl intensity. The 5s # flashes of light may have any of the features described in above. Light that alternately displays different colors Note - The 10. Alternating Al alternating Al WR # light can be 3s used in conjunction with most of the lights earlier classes. See also[edit] + iconEngineering portal + Lighthouse + Pilotage + Signal lamp Notes[edit] 1. ^ Thompson, William. "On Lighthouse Characteristics". Retrieved 21 August 2022. 2. ^ ^a ^b ^c ^d ^e List of Lights 3. ^ ^a ^b Light List states at one point that only "frequency not exceeding 30 flashes per minute" is considered "Flashing", yet at another that only "a rate of 60 flashes per minute" is considered "Quick", leaving the interval in-between undefined. References[edit] + Light List, Volumes 1-7. United States Coast Guard. - Glossary to Aids of Navigation Terms in any of the volumes + Limits of List of Lights, Pubs. 110-116. United States National Geospatial-Intelligence Agency. p. XII - Characteristics of Lights, in any of the volumes + Glossary of Lighthouse Terms External links[edit] + U.S. ATON light characteristic terms illustrated * v * t * e Lighthouses * History of lighthouses * Conservation of lighthouses * Museums * Aerial * Caisson * Crib * Integral Construction * Pile * Screw-pile Types * Skeletal tower * Vessel (acting) * Daymark Navigational purpose * Leading lights * Sea mark * Sector light * Aerobeacon * Argand lamp * Automatic lamp changer * Bird-cage lantern * Carcel lamp * Dalen light Fixtures * Foghorn * Fresnel lens * Lens lantern * Lewis lamp * Light characteristic * VRB-25 [70px-Bri] * Keepers * Light dues Maintenance * Pharologists * Tender * Africa * Antarctica * Asia Locations * Europe * North America * Oceania * South America * Lighthouse builders * Lighthouses by heritage register Categories * Lighthouses by century of completion * Lighthouses by year of completion * General lighthouse authority * International Association of Lighthouse Authorities Global * Amateur Radio Lighthouse Society organizations * International Lighthouse and Lightship Weekend * Lighthouse Digest * # Category * # Commons * # Wiktionary * # WikiProject * Retrieved from "https://en.wikipedia.org/w/index.php?title= Light_characteristic&oldid=1204961302" Categories: * Lighthouse fixtures * Maritime signalling * Navigation Hidden categories: * Articles with short description * Short description matches Wikidata * This page was last edited on 8 February 2024, at 13:43 (UTC). * Text is available under the Creative Commons Attribution-ShareAlike License 4.0 ; additional terms may apply. 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