The Cone Nebula is the small dark  cone at the lower center 
of the image, that is just a fragment of this vast star-forming  
region, 2600 light-years distant.   The Hubble Space 
Telescope took a closeup image of the cone, shown at the 
right.  My image includes a wider one  degree field in the 
constellation Monoceros (the Unicorn), next to Orion and 
Gemini.  The blood-red glow arises from clouds of hydrogen 
gas.  The ultraviolet light of nearby stars excites the Hydrogen 
atom's solitary electron to a higher energy level.  The 
Hydrogen atom then releases photons of discrete energy (and 
thus discrete wavelength) when the gas makes a transition 
back to a lower energy level.  For a more elegant discussion 
of this process, click here.  
Above the Cone Nebula, a loose triangular cluster of stars is 
called the Christmas Tree cluster.  At the top of the image, 
interstellar dust reflects the light of the brightest stars in the 
cluster, glowing blue, which has been called the Foxfur 
Nebula.  This blue glow is created by the same mechanism of 
reflected starlight that causes our own skies to appear blue!
Imaging data:   Exposure times were 120 minutes red, 60 
minutes green, and 80 minutes blue.  An ST2000XM camera 
was used through a TEC 140 mm refractor at the Hidden 
Lake Observatory.
Four years earlier, my image of this region was published in 
Sky and Telescope magazine, accompanying a letter.  You 
can see the article by clicking here.
         
        
         
         
         
         
         
         