A lunation is the Moon's movement from the New Moon to the end of a cycle, which is 28.5 days. As the Moon moves it brings prominent themes through major moon phases and especially the New and Full moons, which indictate the rising action and culmination of the 28 day period.
This tool can help the user determine the astrological themes and narrative of a specific lunation through the houses of an individual's natal chart.
Your Ascendant sign will be needed to calculate this information. You can find this information through any website that helps you view your natal chart. This information is all calculated in Whole Sign, if you use regularly use Placidus, the tool may not work as expected.