The Bible Calendar, a Practical Guide
What is a calendar?
The word “calendar” comes from the latin word “kalendae”, which means to “call out”. In ancient Rome, it referred to the calling out of the first day of the month.
..."the calends" the first day of the Roman month.etymonline.com/?search=calendar
The English word “month” and “moon” are synonymous in their origins.
related to *menon- "moon" (see moon (n.); the month was calculated from lunar phases). Its cognates mean only "month" in the Romance languages, but in Germanic generally continue to do double duty.etymonline.com/?search=month
Old English mona, from Proto-Germanic *menon- (source also of Old Saxon and Old High German mano, Old Frisian mona, Old Norse mani, Danish maane, Dutch maan, German Mond, Gothic mena "moon"), from PIE *me(n)ses- "moon, month" (source also of Sanskrit masah "moon, month;" Avestan ma, Persian mah, Armenian mis "month;" Greek mene "moon," men "month;" Latin mensis "month;" Old Church Slavonic meseci, Lithuanian menesis "moon, month;" Old Irish mi, Welsh mis, Breton miz "month"), from root *me- (2) "to measure," in reference to the moon's phases as an ancient and universal measure of time.
A masculine noun in Old English. In Greek, Italic, Celtic, Armenian the cognate words now mean only "month."etymonline.com/?search=moon
This should help clarify that even in English, the calendar is connected to the moon.
What is the new moon?
There are a few definitions of what the “new moon” is, for the purposes of a calendar from the scriptures only. There are two main definitions that are relevant, the first is the conjunction of the moon, the second is the first visible crescent of the moon.
How can we know which it is? A simple test can determine the answer, which definition requires a man to tell you the answer, and which can you determine on your own? And also, which definition of the new moon creates a debatable event, and which is an indisputable event?
The new moon is the conjunction of the moon, earth and the sun.
The conjunction is an indisputable event that occurs for everyone around the earth at the same time. Everyone can learn how to determine this point of time on their own, or even predict it accurately years in advance, as the movement of the moon is predictable.
The reason the biblical definition of the new moon cannot be the first visible crescent is because it is a debatable event. A person can argue they didn’t see the new moon, and therefore argue that the holy day is the next day. Or if their is clouds, you cannot see the moon, and therefore you yourself may determine a different date based on your own observations.
But the conjunction happens in an instant, and can be predicted days in advance
How to determine when the new moon conjunction will happen
We lack the most basic understanding of the movement of the moon and sun, likely because most of live inside most of our lives. Where as a shephard in Israel thousands of years ago would often sleep outside with his flock, and understood the movements intuitively.
As the month ages, and gets closer to ending, the closer the moon gets to the sun at
The first month
‘On the fourteenth day of the first month at twilight is the LORD’s Passover. Lev 23:5