... Three Nebulae in Narrow Band . ... Credit Copyright: Michael Mayda Explanation: Narrow band filters and a false-color palette give these three nebulae a stunning appearance against the cosmic canvas of the central Milky Way . ... The third, NGC 6559 , is at bottom right. ... In the composite image, narrow emission lines from sulfur, hydrogen, and oxygen atoms recorded through the filters, are mapped into broader red, green, and blue colors respectively. ... IC 1396: Emission Nebula in Cepheus . ...