The autumn equinox is now upon us! Today marks the moment that the sun crosses the celestial equator, ushering in the beginning of astronomical autumn in the northern hemisphere, which brings with it ...

The equatorial coordinate system projects Earth's latitude and longitude onto the celestial sphere, using declination (angular distance from the celestial equator, measured in degrees) and right ...

Spring officially begins today (March 20) with the vernal equinox, bringing longer days and warmer temperatures to the Northern Hemisphere. The vernal equinox signals the astronomical start of spring ...

At 2:19 p.m. EDT on Monday, Sept. 22, 2025, the sun will cross the celestial equator heading south. That marks the fall equinox in the Northern Hemisphere — the first day of autumn — which means ...

Each Monday, I pick out North America’s celestial highlights for the week ahead (which also apply to mid-northern latitudes in the Northern Hemisphere). Check my main feed for more in-depth articles ...

AMHERST, Mass. (WWLP) – Monday marks the autumnal equinox, and the public is gathering at the UMass Sunwheel to observe the celestial event. The equinox signifies the astronomical change of seasons ...