It is traditionally marked on the first Sunday following the spring equinox.

This year's worm moon is special because it coincides with the spring equinox.

His main concern was the calculation of the spring equinox, and from that Easter.

He is particularly associated with the spring equinox, but also with the growing season generally.

His festival is the spring equinox, and he is associated with the astrological sign Aries.

And, more importantly for the church, Easter was out of kilter with the spring equinox.

First a solar eclipse, then the spring equinox.

Naurooz, i.e., New Day-orspring equinox, March 21st.

Today is the spring equinox, when the length of the day and the night are almost equal.

He re-established the spring equinox to the place fixed by the Council of Nice (787).

This is the first time in nearly two decades that a supermoon coincides with the spring equinox.

But winter was on its last legs now, and the spring equinox-March 21-was only two days away.

Last year, the angle of sunlight during Saturn's spring equinox revealed that many of Saturn's rings have mountains.

Why we allow some kind of national masochism to push "winter" time beyond the spring equinox.

The festival is fixed onto the first Sunday after the first full moon following the northern spring equinox.

We passed New Zealand with the spring equinox and the winds, though strong, were at no time violent.