What's the date of the first day of the eighth lunar month this year?

This year, the first day of August in the lunar calendar is September 15th. This year is 2023. By querying the calendar website, we know that the first day of the eighth lunar month in 2023 is September 15. The lunar calendar is a traditional calendar in China. It takes the change period of the moon phase as the length of the month, adds the "twenty-four solar terms" component of the trunk calendar, and refers to the length of the tropical year of the sun. By setting leap months, the average calendar year is adapted to the tropical year.