Constellations are drawn as stick figures connecting bright stars in the sky. This two-dimensional representation gives the impression that the stars are all at the same distance. In addition, the idea of a "bright star" can be misleading, as the apparent brightness we see depends upon both the star's intrinsic brightness and its distance from Earth. This scientific visualization addresses both of these issues by viewing the Orion constellation from a three-dimensional perspective. The true space distribution of the constellation as well as how stellar brightness changes with viewing position is revealed by circling around the stars.
The camera begins with a pan across the sky to Orion. The lines of the 2D stick figure constellation are drawn in. As the camera slowly begins to circle around the centroid of the stars, the stick figure quickly breaks into a long, extended 3D structure. The camera backs up to keep the entire figure onscreen for the complete circle. At the end of the circle, the camera pushes forward to finish at the location of the Earth/Sun (to avoid an obvious distraction, the Sun is not included in the visualization).
During that final camera push, notice how Sirius grows in apparent brightness (bottom of frame, just left of center). While Sirius is the brightest star in our night sky, a major contribution of its apparent brightness comes from its proximity to the Sun.
Production date: May 20, 2011
F. Summers (STScI)