Astro Bob blog: Help yourself to two slices of pieWhether morning or evening, you'll face a stellar triangle in the nighttime sky.
By: Bob King, Duluth News Tribune
Help yourself to two slices of pie
This map shows the sky for tonight with the waxing moon at upper right. The Winter Triangle is easy to find in the south through mid-March during the early evening. The cloudy band is the Milky Way. Maps created with Stellarium
For most of us one slice of pie is plenty but for the astronomically inclined, we may help ourselves to two this month and next. I'm referring to the two large triangles of stars -- one in the evening, the other in the morning -- that call our attention in the night sky.
While the constellations have their individual patterns and associated stars, many of us love to go to the next level of pattern-making by constructing superconstellations using stars from multiple sources. Case in point is the Winter Triangle, now prominent in the evening at the convenient hour of 8 o'clock. It's formed from Procyon of the Lesser Dog, Sirius from the Greater Dog and Betelgeuse from Orion the Hunter. With three nearly equal sides and angles, the triangle formed is close to being equilateral. I don't know when this figure originated or by whom, but it's bright and crisp and a big help in finding other constellations in Orion's neighborhood.
The Summer Triangle is highest in the eastern sky at the start of dawn. Vega, the topmost and brightest star in the figure, is Lyra the Harp's brightest star; Deneb heads up the Northern Cross, also known as Cygnus the Swan, and Altair is the brightest star in Aquila (AK-will-uh) the Eagle.
Our second triangle is the familiar Summer Triangle visible in the early morning at dawn's first blush. It's more of an acute triangle, where none of the angles is greater than 90 degrees. This triangle is larger than the winter version with the two long sides about three outstretched fists in length. Two fists separate Deneb and Vega. Coincidentally, the Milky Way crosses through the center of both winter and summer triangles though the summer version is considerably brighter and easier to see.
The changing starscape of the morning sky reminds us that warmer weather and longer days are on the way. My friend Greg, who arises before dawn to drive to work each day, is cheered by the trio of Deneb, Vega and Altair in the east. It's balm for his summer-starved soul. Perhaps you need some cheering, too? It's waiting for you the next clear morning.
This time exposure photo taken this weekend shows the Milky Way and the Summer Triangle. Details: 16mm lens at f/2.8, ISO 1600 and 25-second exposure. Photo: Bob King