Russell Croman photographs space from his backyard observatory in Austin, Texas. He made this image on Aug. 17.

It shows a star cluster surrounded by clouds of gas and dust, collectively called IC 1396.

Croman made three separate long exposures using different filters to highlight certain elements that are excited by starlight. He then combined the images into one photograph.

"Blue represents oxygen, which takes the most energy to excite," Croman explains. "Next easiest to excite is hydrogen, which is represented by green. Sulphur, color coded red, is the easiest element of the three to ionize. From the resulting color patterns, one can see the influence of the bright stars at the center of the nebula, which are the sources of ultraviolet radiation that power it."

Below center is a prominent feature known as the Elephant's Trunk nebula.

"It is a dark globule of gas and dust being eroded by the radiation pressure from the bright stars above it," Croman says. "Numerous other such globules of varying size are scattered throughout the nebula. Some of these are positioned between us and the bright clouds of gas, and so appear as inky black silhouettes."