Tonight – February 24, 2018 – the waxing gibbous moon shines inside a large asterism that we in the Northern Hemisphere often call the Winter Circle. It’s a very large star configuration made of brilliant winter stars. Around the world on this night, the moon is inside the Circle. From anywhere in the Northern Hemisphere, look for this pattern to fill up much of the eastern half of sky at nightfall. By mid-evening, the Winter Circle will swing to your southern sky, and then it will drift into your western sky around midnight.
If you’re in the Southern Hemisphere … although it’s not winter for you, these same stars appear around the moon. But, for you, the Circle will appear upside-down with respect to our chart. The star Sirius will be at the top, instead of the bottom.
The Winter Circle is sometimes called the Winter Hexagon. It’s not one of the 88 recognized constellations. Rather, it’s an asterism – a pattern of stars that’s fairly easy to recognize. Our sky chart can’t adequately convey the Winter Circle’s humongous size! It dwarfs the constellation Orion the Hunter, which is a rather large constellation, occupying the southwestern part of the Winter Circle pattern.
Here’s how to locate the Winter Circle from mid-northern latitudes. At nightfall and early evening, look high overhead for the bright star Capella. This star marks the top (or more properly, the northern terminus) of the Winter Circle.
As Capella shines way overhead, the constellation Orion the Hunter is prowling in the southern sky. Draw a line downward through Orion’s Belt to find Sirius, the brightest star in the night sky. This star marks the bottom (the southern tip) of the Winter Circle, as seen from our Northern Hemisphere perspective
By the way, tonight’s waxing gibbous moon shows you where the sun resides in front of the backdrop stars in late June or early July. So enjoy the Winter Circle. And contemplate the sun being in this part of the sky when summer returns to the Northern Hemisphere!
Bottom line: On the evening of February 24, 2018, the waxing gibbous moon shines inside the huge pattern of stars known as the Winter Circle. Be sure to notice the different colors of these stars!