Page 3 of 18 of my suggested calendar ' THE PEOPLES ERA CALENDAR' .

Making a moon calendar is scientifically correct.

It has become clear as day that the moon completes its cycle around the earth in a month and in conjunction with the earth it completes its cycle around the sun in a year.

Units of the month and week have come into being from the changing forms of the moon.

Today in the fifty-six Islamic countries of the world, every new month, year, century and millennium of the Islamic calendar begins with the appearance of the new crescent moon. At the beginning of the 7^th day this New Crescent Moon changes into a perfect half-round disk which at the beginning of the 14^th day changes into a perfect round disk which on the morning of the 21^stday once again looks like a perfect half-round disk which, on the morning of the 28^th day, appears in the form of Old Crescent Moon which  disappears from the sight for the next one or two days before it once again reappears as the new crescent moon. If the New Crescent Moon appears after one day then that month is counted as of 29 days. And if it shows up after two days then the month is counted as of thirty days (See appendix I of VII).

The moon is also called the heavenly clock.

Just as digital clocks are used to identify 24 hours of the day and night, all the days of a month passing through the sky are identified by the changing patterns of the moon. (See appendix I of VII).