Saturn [at the apex], Spica [lower left], and Mars [lower right] form a nice equilateral triangle in the sky just after sunset.
Spica, 260 light years from Earth, is mis-classified as a "blue giant" - but it is actually a pair of stars so close together that they cannot be resolved through a telescope.
The primary star has more than 10 times the mass of the sun and 7 times its radius. It rotates rapidly, and varies in brightness over about a four-hour period due to expansion and contraction of its surface. The secondary member of the Spica system is smaller than the primary, with about 7 times the mass of the Sun and 3.6 times the Sun's radius. Seen as a single star, Spica is brightest star in the constellation Virgo and the 15th brightest star in the nighttime sky.
![Saturn, the star Spica, and Mars form a nice triangle in the sky left of center, just after sundown. [Might be difficult to see in this image due to image size and monitor resolution.]](https://images.squarespace-cdn.com/content/v1/5005dbf284aebe9f4d09d4f5/1344484368003-B17R4ERHWYJGIF2HF2P4/1232-_P2A-0093.jpg)
Saturn, the star Spica, and Mars form a nice triangle in the sky left of center, just after sundown. [Might be difficult to see in this image due to image size and monitor resolution.]
Close-up of the Martian Triangle.