Preview NGC 6826, Caldwell 15, Composite Image ID: 1349-157 Artist: NASA/CXC/RIT/STScI Purchase a commercial license Buy framed prints & more from our print store 2012 21st century astronomy blinking nebula blinking planetary caldwell 15 celestial body composite image deep sky deep space emission nebula interstellar cloud nebula ngc 6826 planetary nebula science star formation stellar remnant nebula