This is the later and improved method used as a calendar to follow the solar year through the seasons. Shown here is another calendar, and an easy method of telling the time of year, and forecasting accurately the solstice day and time. Measuring movement over some days makes for a more accurate forecast.
Ggantija North is adjacent to an older calendar, both having nearly same orientation. However the equinox to solstice angle in the later unit is 18deg, as against a previous 23deg in the older one. Reason for building a second unit on same orientation. Date: just after ~3550bce.
Ggantija North became suddenly obsolete due to the 3200bce event. View the main solstice stones here courtesy Google Earth: https://firstname.lastname@example.org,14.26913,3a,90y,353.28h,103.57t/data=!3m8!1e1!3m6!1s-C4E_yNv9veg%2FWJvFqfbHipI%2FAAAAAAAALio%2Fu3IRmda5rCoh0mnR3k4s3EuzsTixkFEJgCLIB!2e4!3e11!6s%2F%2Flh6.googleusercontent.com%2F-C4E_yNv9veg%2FWJvFqfbHipI%2FAAAAAAAALio%2Fu3IRmda5rCoh0mnR3k4s3EuzsTixkFEJgCLIB%2Fw203-h100-k-no-pi-0-ya264.65637-ro0-fo100%2F!7i5376!8i2688?hl=en-US