Editing Leading lights (section)

{{short description|Navigational tool}}
{{for|the racehorse|Leading Light}}
{{more citations needed|date=May 2012}}
[[Image:NantucketRangeLites.jpg|thumb|right|[[Nantucket Harbor Range Lights]]<ref name=cgll>{{cite uscgll|1|2009|135}}</ref> The [[dayboard]]s are type KRW, see below.]]
[[Image:Bremerhaven Unterfeuer 1.jpg|thumb|[[Bremerhaven Lighthouse|A pair of leading lights in Bremerhaven]], Germany, with the rear light in a proper lighthouse and the front light on a smaller tower. No standardised markings are used here.]]

'''Leading lights''', also known as '''range lights''' in the [[United States]], are a pair of light beacons used in [[navigation]]<ref>{{cite web|url=http://www.ialathree.org/dictionary/index.php?title=Leading_Lights_%28G.B.%29 |title=Dictionary of the International Association of Lighthouse Authorities |publisher=[[International Association of Lighthouse Authorities]]}}</ref> to indicate a safe passage for vessels entering a shallow or dangerous channel; they may also be used for [[position fixing]]. At night, the lights are a form of [[Piloting#Piloting in channels and rivers|leading line]] that can be used for safe navigation. The beacons consist of two lights that are separated in distance and elevation, so that when they are aligned, with one above the other, they provide a bearing. Range lights are often illuminated day and night.

In some cases the two [[beacons]] are unlighted, in which case they are known as a ''range'' in the United States or a ''[[Navigational transit|transit]]'' in the UK. The beacons may be artificial or natural.