These calendars are pretty much showing you what lunar phase you will be getting at any time of the month. Contrary to popular belief, the moon follows really foreseeable patterns - it isn't arbitrary by any means. Its movements have been researched for a long time and researchers know its exact spot and what phase it will be in at any given time.
But really, who cares about this issue? The reply is lots of people!
You see, our minds and our emotions have a very close connection to the moon and its location. If you do a little research and learn all the different meanings of things on the subject of astrology moon signs, the moons position, and numerology in general, you will be amazed at simply how much all this stuff is connected and the way all of it works together. The precision of the info you can learn about you through this is usually a little scary!
When you begin to examine yourself and try to find answers about why you are the way you are and why you conduct yourself the way you conduct yourself, you startto grow as a person.
If you're looking for something entertaining to try to to, go locate a lunar calendar and learn what moon phase you are going to be experiencing. When it gets dark out, head somewhere where you will be able tosee the moon clearly, just take a seat and view.