BETHLEHEM, Pa. — Brad Klein reviews upcoming astronomical highlights with Bethlehem’s ‘Backyard Astronomy Guy,’ Marty McGuire.
This week, the subject is the beginning of ‘astronomical autumn.’
There are several ways to calculate the start and end of the seasons. So-called ‘meteorological autumn’ runs from Sept. 1 through the end of November. It’s a convenient way to assign each season three calendar months.
But for the astronomically-minded, fall begins with the equinox, “Monday, Sept. 22 at 2:19 p.m. to be precise," according to McGuire.
That is the moment of the September, or autumnal, equinox here in the Lehigh Valley. For people living south of the equator, it marks the vernal equinox and the beginning of their spring.
Meanwhile, here in the Lehigh Valley, the days continue to get shorter until we reach our next orbital milestone, Dec. 21, 2025, the winter solstice.