Keeping track of dates are really important to all of our lives. We need to know what we are doing daily and be very organized so we can function well in our daily lives. Calendars are some of the objects that human beings use in order to remain organized in their professional and personal lives. I have two calendars that I use to keep my life well organized. I have a wall calendar in my bedroom and I carry a small appointment in my purse to make sure that my days, weeks, and months go as smoothly as possible. As I have stated before calendars are vital tools in human beings lives. However, there are other types of specific calendars that human beings need to be aware of and study from time to time. These types of calendars are called the lunar calendar and the Jewish calendar. The lunar calendar is important in terms of the solar system and the Jewish calendar has important religious significance for Jewish people in terms of the Jewish holidays.

Anything involving the word 'lunar' involves the moon. The moon is part of our solar system. There are lunar eclipses and solar eclipses. Also, many astronauts have been to the moon. Did you know that Neil Armstrong was the first American man to walk on the moon? There is also a claim that the moon is made of green cheese; but I think that claim was made by a bunch of very hungry mice or rats. There are also many moon phases. A lunar calendar is used in conjunction with the moon's activity. A lunar calendar is a calendar oriented at the moon phase. This is normally done by having a month that corresponds to a lunation so that the day of the month indicates the moon phase. If the calendar also tracks the four seasons of winter, spring, summer, and fall, it is also called a lunisolar calendar. Since there are about twelve lunations which are also called synodic months in a solar year, this period is sometimes also called a lunar year, corresponding to thirteen sidereal months.

Most lunar calendars are also lunisolar such as the Hebrew calendar which is also called the Jewish calendar, Chinese calendar, Tamil calendar, the Hindu calendar, and most calendar systems used in antiquity. The reason for this is that a year isn't easily divisible by an exact number of lunations so without any corrections the calendar year will drift with respect to the four seasons of winter, spring, summer, and fall. The only widely used purely lunar calendar is the Islamic calendar because it always has twelve lunations in its year. As a result of this, it is used mostly for religious purposes along with secular solar calendar, and Islamic feasts perform a full circle in respect to the four seasons every 33 years.

For some lunar calendars such as the Chinese calendar, the first day of the month is determined by the day during which the movement of the new moon arrives, according to a particular time zone. Many other lunar calendars are based on the first sighting of the lunar crescent. Therefore, different lunar calendars differ in which day is considered the first day of the month. I wonder if a lunar calendar can tell people when there are going to be a full moon so that they can beware of werewolves.