Enjoying EarthSky? Subscribe.

269,790 subscribers and counting ...

Moon in Winter Circle on April 19

Tonight – April 19, 2018 – look for the moon and Winter Circle (or Winter Hexagon) stars. It’s difficult to convey the humongous size of the Circle, a great lasso of brilliant stars that fills our western sky at dusk and nightfall.

Look for a circular (or hexagonal) pattern of bright stars around the April 2 moon. Just be sure to look at nightfall, because the Winter Circle stars will sink below the horizon by early evening.

Chirag Upreti was in Harriman State Park, New York when he caught this shot of the moon and Winter Circle (or Winter Hexagon) on April 2, 2017. He wrote: “The crescent moon illuminated ~42% seen inside the asterism of the Winter Hexagon. Rigel is low and seen between the tree line on the horizon. The passing clouds and the lens flare on the gave a sci-fi feel to the picture at first glance.”

Gowrishankar Lakshminarayanan on Long Island, New York also caught the April 2 moon inside this great circle (or hexagon) of stars.

The Winter Circle can be seen from around the world, although its orientation with respect to the horizon will be different, depending on where you are.

No matter what part of Earth you’re standing on, though, this same pattern of bright stars will surround the moon on April 19.

If you’re in the Southern Hemisphere, notice the sky’s brightest star – Sirius – will appear at the top of the Circle and the star Capella at the bottom (if you can see Capella at all; it’s far to the north on the sky’s dome).

The orientation of stars with respect to the horizon – and their height above the horizon – is different as seen from different parts of the globe. Here’s a gorgeous shot from March 30, 2017 of Orion and Canis Major – containing the sky’s brightest star Sirius – as captured from the Philippines on March 30, 2017. Photo by Gabriel Obusan.

The Winter Circle stars are bright, but the brightest starlike object in the sky on these April 2017 evenings is the planet Jupiter. At nightfall on April 2, the moon and Winter Circle are in the west, while Jupiter shines in the opposite direction – east – and quite close the horizon after sunset. Earth is about to go between Jupiter and the sun, and so the planet is nearly at its brightest for this year. Jupiter’s yearly opposition will come on April 7.

Enjoying EarthSky so far? Sign up for our free daily newsletter today!

In any year, you can follow an imaginary arc in the handle of the Big Dipper to the bright stars Arcturus and Spica. This year, 2017, is extra special because the dazzling planet Jupiter beams close to Spica all year long.

Here’s another way to find Jupiter, via the very noticeable, small, square-ish constellation Corvus the Crow.

Bottom line: Use the moon on April 19, 2018, to find the bright stars of the Winter Circle!

Bruce McClure