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During the early weeks of spring, the most widely recognized constellation at nightfall is Orion, standing upright in the southwest. People who appreciate the outdoors may know this prominent constellation best. Here are Orion constellation facts and viewing tips from Almanac astronomer Bob Berman.
For us during these first weeks of spring, Orion’s famous 3-star Belt floats nicely high in the southwest as soon as darkness falls. What better place to start strolling the universe’s boulevards? The three stars float like a navigational buoy in the middle of the sky.
Can the sky really have a “middle?” Yes, because Orion’s belt, that most fashionable article of cosmic clothing, sits smack on the celestial equator—meaning it floats directly over the equator of Earth.
Only stars in that location are seen by everyone everywhere. A star over one of the poles—the north star, say—is forever cloaked from people of the opposite hemisphere, obstructed by Earth itself. From most of the United States, about a fourth of the cosmos never rises. Major luminaries forever concealed from view for Canadians, Americans, and Europeans include the nearest bright star (Alpha Centauri), the night’s second brightest (Canopus), and the Southern Cross.
But equatorial constellations are the lingua franca of space. Orion’s belt, straddling the equator like a diplomat, is displayed around the world.
While most cultures picture it as a belt, a few thousand years ago the Sumerians visualized it as the waistline of a sheep. Apparently, this designation was too ludicrous to endure, and in a wonderful wooly rags-to-riches story, Orion overcame his ovine birth and got promoted to human.
The Hunter’s stars are not scattered randomly. Most share the same awesome 900–2,000 lightyears distance, forming a lavish association of blue suns of arc-welder intensity. Merely 1/1000th the age of Earth, these infants were born together from an immense cloud of gas that still dreamily envelops the constellation and shows up in wide-field telescope photos.
From any non-light-polluted region away from city lights, binoculars pointed at the belt show it immersed in a gorgeous multitude of faint stars like a swarm of fireflies. In truly rural areas, this faint, unnamed cluster is glimpsed with the naked eye.
Equidistant above and below the belt stand two brilliant stars—the yellowish hue of cool red supergiant Betelgeuse represents Orion’s shoulder and contrasting blue-white supergiant Rigel is Orion’s other dominant star which marks the Hunter’s knee.
Betelgeuse is the largest star in all the heavens and stands about halfway between us and all those blue-white suns that make up the rest of the constellation. It’s the gateway to the fabulous city beyond, Orion’s dazzling sapphires that will adorn the early evening sky every year of our lives.
Rigel is Orion’s brightest star, shining with the light of 55,000 suns. If it were as nearby as Alpha Centauri, we could read by its light—and the night sky would be deep blue instead of black.
The sword of Orion hangs from the Hunter’s three blue belt stars, but the middle star in the sword is not a star at all. A slightly fuzzy glow hints at its true nature, a nearby stellar nursery visible to the unaided eye known as the Orion Nebula. Cameras attached to telescopes reveal this to display crimson, emerald and blue knots, whose dancing eddies magically sprout the fires of newborn suns.