Talk:Dark moon

Picture worth 1000 words

I've read this article several times and still don't understand what it's trying to say. Understandably, there are numerous definitions of dark and new moons, possibly because of confusion. It would be good, IMO, if the phases of the moon (some days before and after the astronomical new moon) were diagrammed along with labels describing the exact points or vague areas referred to as astronomical, Babylonian, Hebrew, Indian, colloquial, and other dark and new moons. — Preceding unsigned comment added by 84.208.116.66 (talk) 15:18, 28 October 2019 (UTC)

Astrological influences

Apparently, there are astrological influences of a Dark Moon, the details of which need to be entered here. —Preceding unsigned comment added by 160.79.176.162 (talk • contribs)

Why is this article within the scope of WikiProject Astronomy?

To my knowledge, the term "dark moon" is never encountered in astronomy, so is it appropriate to have it within the WikiProject Astronomy? The terms "lunar dark time" and "dark of the Moon" are used in astronomy to denote the period around 8 to 12 days long centred on new Moon when the Moon causes minimum disruption to observations of faint objects; but not "dark moon". — Preceding unsigned comment added by TowardsTheLight (talk • contribs) 19:55, 9 July 2012 (UTC)

According to a quick search of Google Books, the term is well used in astrology, so I've added a WikiProject Astrology banner. I also know that in calendar discussions the term "new moon" is used for two different but related events. One is the astronomical new moon and the other is the thin crescent moon observed just above the western horizon, both of which have been used in various calendars to mark the first day of a lunar month. To avoid confusion, the astronomical new moon is sometines called the "dark moon" to distinguish it from a new moon that is actually the crescent moon. This tenuous use links it to astronomy. I do not know of a more direct use in astronomy. Nevertheless, I'm also adding a WikiProject Time banner, because it includes calendars in its purview. By the way, the crescent moon is named hilal by Muslims. — Joe Kress (talk) 17:59, 10 July 2012 (UTC)

Thanks. I did wonder whether dark moon was a term from astrology. Adding it to WikiProject Astrology is therefore sensible. It's not a term I've ever come across in astronomy. Many thanks for the clarification. TowardsTheLight (talk) 18:38, 10 July 2012 (UTC)

Now what does it mean?

The first line says: "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, ...".

This is inconsistent: the last visible crescent of a waning moon would be visible for maybe a few minutes before sunrise (as is the first crescent after sunset), and certainly not for a period of up to 3.5 days.

There appear to have been 3 different meanings which get mixed up here, all of which appear to be poorly documented.

• In the original version of the article "dark moon" referred to the geocentric astronomical conjunction of Sun and Moon in ecliptic longitude, which is the astronomical definition of a New moon (and which can be precisely calculated and is 1 moment in time), to distinguish it from the well-documented traditional meaning of the term "New Moon" which was the first visible crescent at evening after the conjunction (which depends on the observer and its location).
• Then later someone re-defined it as the period of a few days around the conjunction when the Moon cannot be seen;
• and still later someone re-defined it as the last crescent that can be seen before sunrise, before the conjunction.

There are now some references to non-English traditions that name this last crescent: but it is not obvious that those could be translated as "Dark Moon".

So I propose to recognise that the term has had different meanings and list them in this article, preferably with references to actual use; and not re-write this article with a different meaning all the time.

Tom Peters (talk) 09:15, 8 August 2022 (UTC)