Vernal equinox: Stargazers in UK can watch these three stars tonight to mark official arrival of Spring

The vernal equinox, which marks the official beginning of spring in the Northern Hemisphere and autumn in the Southern Hemisphere, takes place on March 20 this year. This moment occurs when Earth's axis is aligned side-on to the sun, spreading equal amounts of light and heat across the globe.

According to Live Science, the equinox is a moment of balance, signalling the transition from one season to the next. Stargazers can spot this change by observing certain stars and constellations visible only at this time of the year in the Northern Hemisphere's spring sky. The easiest way to witness the seasonal shift on the equinox is by looking southwest after sunset, where the three bright stars in Orion’s Belt — Alnitak, Alnilam, and Mintaka — will guide the way.

Above these stars, you’ll see Betelgeuse, a prominent reddish star in the constellation, and below the belt is Rigel. To the left and slightly below Orion’s Belt, you’ll find Sirius, the brightest star in the night sky. These stars form the Winter Triangle, marking the end of the winter season.

For a clear celestial confirmation of spring, look toward the north where the Big Dipper, also known as the Plough, will be riding high in the sky. As Live Science explains, the seven bright stars of the Big Dipper can be used to locate the Spring Triangle, an equilateral triangle made of three springtime stars: Arcturus, Spica, and Denebola.

To locate the Spring Triangle, follow the curve of the Big Dipper's handle to "arc to Arcturus," a bright reddish star to the east. Then, "spike to Spica," a bluish star rising in the east-southeast, and look directly above to find Denebola in the constellation Leo.

While these three stars can be seen with the naked eye, a backyard telescope or binoculars can enhance the viewing experience. The Spring Triangle will remain visible in the night sky until August, when the transition from spring to summer occurs.