Nebulae
The enigmatic nebulae range from compact planetary forms to disperse gaseous clouds and reflection nebulae. Colors reveal the chemistry of the gases, with red the main emission of ionized H-alpha (656 nm), blues mainly doubly-ionized O (~500 nm), and for reflection nebula blue from light scattering.
GALLERIES (click images) -- Originals by Rex A. Parker PhD, processed from data acquired at 3 telescope locations: (1) my home observatory in central New Jersey USA; (2) Cerro Tololo, Chile (Star Shadows Remote Observatory run by S Mazlin, WM Hanson, and RA Parker through UNC-Chapel Hill Astronomy Dept; (3) Mt Lemmon Sky Center, Arizona USA, data thanks to A Block.