A week ago under a dark sky I spotted a faint nebula dubbed Sharpless 2-106 in the constellation of Cygnus, better known as the Northern Cross. It’s one of 312 nebulae cataloged by American astronomer Stewart Sharpless in the late 1950s.
Sharpless studied glowing clouds of hydrogen gas littered across the Milky Way galaxy like smoke from so many campfires. Only these clouds glow from the light of brand new stars forming within their dusty pockets and folds.
To the eye, the nebula was only a faint puff of light about the size of a planet seen through a telescope. I had to use a magnification of 257x to see it best; even then S106 would have been easy to miss without a good sky chart. Yet in eyes of the Hubble Space Telescope’s camera, the nebula becomes a fairyland of sparkling stars and pink mist.
Superhot gases blasted into space by powerful winds blowing from a massive newborn star at the nebula’s center shape the two blue lobes. A ring of thick, dark dust hides the star from view and acts as a belt, cinching the expanding nebula into an hourglass shape. Through my telescope only the brighter lobe was seen.
While the star may be invisible, its light paints the expanding bubbles and the wispy filaments that thread the nebula both by reflected light and excitation of hydrogen gas by the star’s ultraviolet light.
Pictures taken in infrared light, such as those by the Subaru Telescope, have found the central star has lots of company. Besides fresh-born sun-like stars, some 600 young brown dwarfs riddle the nebula – tiny stars less than 1/10 the size of the sun that are too small to sustain the nuclear burning that powers a typical star. The lightest of these have masses only few times that of Jupiter.
Amazing, isn’t it, how celestial objects look through a telescope compared to the “dressed up” view through a large, camera-equipped scope? You might wonder if seeking out something at the edge of vision is worth the bother when you can just look at a photo. I must answer with an unqualified Yes! There’s nothing like the real thing. And when your observations of sky objects are informed by work done by amateur and professional astronomers, what you see becomes all the more wonderful.
For another perspective on what you see vs. what you expect, please check out the story Technicolor Auroras? A Reality Check I wrote for Universe Today. I welcome your comments on either topic.