By Danna Martinez
Lunisolar. The moon and the sun are two spherical astronomical bodies that have mass and volume. Their relationship consists of belonging to the broad context of space. The word lunisolar in its etymology is formed from the Latin «lūna» moon, «Solis» sun and the suffix «ar» that the adjectives mean condition, relationship, or belonging. This term involves the mutual relationship or combined attraction of the moon and the sun.
The first known use of lunisolar was in 1691.
These two, star (sun) and natural satellite (moon), are essential for the measurement of time in calendars, which are classified into three main categories:
- The solar calendar: This calendar is the most commonly used. The solar calendar is those whose days indicate the earth’s position in its translational movement around the sun. The calendars made in this way have a year of 365 days, which is generally extended by adding an extra day in leap years.
- The lunar calendar: A lunar calendar is a way to calculate the time according to the moon. Each lunar month corresponds to 29.53 solar days. The moon’s rotation around the earth takes 27.322 days. The lunar phases are produced by the interaction between the sun, the moon, and the earth. According to the Sciencing website, “The lunar calendar uses the phases of the moon to measure time, usually measuring the time from new moon to the new moon as one month. Astronomers call the time between new moons a synodic month.” Moon’s phases are New Moon, First Quarter, Full Moon, and Last Quarter. In some cultures, a lunar calendar serves to know the moon’s position at all times and to know what factors influence various tasks.
- The lunisolar calendar: This calendar converges both of the calendars mentioned above, the solar and the lunar. This calendar consists of the years related to the earth’s movement around the sun and the regular cycles of the moon’s phases related to the moon’s motion around the planet. For more information about how to create a lunisolar calendar, click here.
For example, The Hebrew calendar is lunisolar. Since ancient times, the Hebrew people knew how to calculate a month’s cycle through the moon’s phases and motion. For the Hebrews, on its journey around the earth, the moon had 29 days, 12 hours, 44 minutes, and 3.33 seconds, which has only a small calculation error of half a second. The Hebrew calendar uses 29-day and 30-day months, interspersing them.