HDWG revised the definition of "The phase of a navigational light" to agree with that used in S-4 (Ex M-4) and this was adopted by Member States. The CSPCWG has subsequently revised their definition to align with IALA and have asked HDWG to review the S-32 definition.
The existing and the new definitions do not disagree with one another however the new definition does include additional elements: "different luminous intensities" and "duration".
I appreciate the well documented CSPCWG proposal and concur with Jerry Mills conclusion.
With the HDWG agreement, I suggest to approve the following definitions:
S-32 New English definition:
Phase of a navigational light:
A visually discrete part of a light signal. It is bounded by changes between darkness and light, or between different colours, or between distinctly different luminous intensities, and it may be further discriminated by its duration.
S-32 New French definition:
Phase d’un feu :
Manifestation observable et discrète d’un feu, caractérisée par des alternances d’éclairement et d’obscurité, ou de couleurs, ou d’intensité lumineuse, ainsi que par la durée de ces alternances.
S-32 New Spanish definition:
(To be completed)
This should complete the HDWG Work Plan 2013-2014, task B7.
Given that the terms "flash" (or "flashing") and "eclipse" are commonly used terms when describing light phases (e.g. in Light Lists) and are included in the current Hydrographic Dictionary definition (and "eclipse" is itself defined in the Dictionary), suggest a slight modification to the proposed definition, indicated in bold text below, so as to read:
A visually discrete part of a light signal. It is bounded by changes between darkness and light (e.g. an eclipse or flash), or between different colours, or between distinctly different luminous intensities, and it may be further discriminated by its duration.
This change has been inserted in the latest revision of the HDWG report to HSSC5, with a slight difference consisting of replacing "eclipse" by "occultation" to remain consistent with the on-line dictionary which specifies:
Occultation (3509): The concealment or extinguishment of the light of an aid to navigation during the dark periods of its cycle...
Eclipse (1550): The obscuration of a source of light by the intervention of an object...
The two words are identical in English and French, although the French tend to use 'Eclipse' in astronomy. The same applies to the Chinese ( 日食 = eclipse; litterally 'sun eat').