Editing Dark moon

{{short description|Last visible crescent of waning moon}}

{{use dmy dates|date=May 2021}}{{more citations needed|date=August 2014}}

{{other uses}}{{distinguish|black moon}}

[[file:fase 16.jpg|thumb|A waning moon]]

The term '''dark moon''' describes the last visible [[crescent]] of a waning [[Moon]]. The duration of a dark moon varies between 1.5 and 3.5 days, depending on its [[ecliptic coordinate system|ecliptic latitude]]. In current [[astronomical]] usage, the [[new moon]] occurs in the middle of this dark period,<ref>{{cite web |last1=Maclin |first1=Ellie |title=Dark Moon vs. New Moon |url=https://sciencing.com/dark-moon-vs-new-moon-5082.html |website=Sciencing |publisher=Leaf Group Ltd. |access-date=24 February 2019}}</ref> when the Moon and [[Sun]] are in [[conjunction (astronomy)|conjunction]]. This definition has entered popular usage, so that calendars will typically indicate the date of the "new moon" rather than the "dark moon".

== Dark moon as the 30th division ==

The ''[[Oxford English Dictionary]]'' defines the [[new moon]] as "the first visible crescent of the Moon, after conjunction with the Sun". ''Dark moon'' is a term used for a waning crescent moon. When the [[orbit of the Moon|Moon's orbit]] is divided into [[lunar mansion|30 segments]], as the [[Ancient Greece|ancient Greeks]] did in the time of Homer, the [[Babylonia]]ns did, and the Indians still do today (calling them ''[[tithi]]''), the last phase is called the "dark moon". In Greek, it was called the "old moon" and associated with [[Hecate]].<ref>{{cite book|last1=Most|first1=Glenn|title=Hesiod Volume 1: Theogony. Works and Days. Testimonia.|date=2006|publisher=Harvard University Press|location=Cambridge, Massachusetts}}</ref> In India, it is called [[Amavasya]] and associated with [[Kali]].<ref>Cole, Freedom. Amāvāsya and Pratipad. ''Jyotish Digest'', Vol XI, Issue II, April–Sep 2014</ref> Both of these goddesses have a dark connotation, hence the term dark moon.

In Babylonian, Greek, and Indian culture, the dark moon occurs within the 12° of [[angular distance]] between the Moon and the Sun before [[conjunction (astronomy)|conjunction]] (a type of [[syzygy (astronomy)|syzygy]]). The new moon occurs within the 12° after syzygy. This 12° [[arc (geometry)|arc]] is called ''uma'' by the Babylonians and ''tithi'' by the Indians.

The Moon takes a mean duration of 23 hours and 37 minutes to cover this length, but this period can vary from 21 to 26 hours because of the Moon's orbital [[lunar theory|anomaly]]. This means that the "dark moon" actually lasts approximately 23 hours and 37 minutes and includes any time marked as "new moon" on a [[lunar calendar]], and not 1.5 to 3.5 days as stated earlier.

== See also ==

* {{annotated link|Amavasya}}
* {{annotated link|Black moon}}
* {{annotated link|Lunar phase}}
* {{annotated link|Syzygy (astronomy)}}

== References ==

{{reflist}}{{the Moon}}{{moon-stub}}

{{DEFAULTSORT:Dark Moon}}

[[category:new moon]]
[[category:phases of the Moon]]