Traditionally, the Dark Moon referred to the period of time when the moon exhibits zero illumination (ie, not able to be seen in the night’s sky), while the New Moon starts the very first day that the moon appears as a slim sliver of light. This means that the Dark Moon occurs only one day during the whole lunar cycle while the New Moon lasts approximately seven days, from a Waxing Crescent, right up until the First Quarter of illumination.
While this may appear simple and straight forward, many calendars, even some “lunar” ones, however list the New Moon as being on the date of or even the day before the Dark Moon, while the moon is still in a Waning Crescent phase. Where does this confusion spring from, and why is it being perpetuated?
The reason for this apparently lies in the difference between the traditional / spiritual definition, and modern scientific terminology. Traditionally, both astronomers and spiritual studies defined the Dark Moon as the date where the moon is at a liminal point in the lunar cycle, exhibiting zero illumination between its waning and waxing phases. This dark stage of the lunar cycle is when the moon is in conjunction with the earth and the sun (ie, it is located directly between the two) and therefore, the moon is cast into shadow. Modern-day astronomers and scientists refer to this time of conjuncture as the New Moon, and this parlance is what has been adopted into both many calendars (both online and printed) today.
Therefore, while the terms Dark Moon and New Moon really are technically interchangeable given that they are referring to the same period of time where the moon is lined-up with the earth and sun, and therefore exhibits zero illumination, from a magickal and spiritual perspective they hold different connotations, especially due to the different energies. It is recommended, therefore, to check with online lunar calendar that details visible illumination when planning any work that involves the moon and the corresponding energies of its various phases.
This article has been adapted from Speak of Secrets.