NGC 896 / IC 1795 / LBN 645: "Fish Head Nebula"

This image is of close-up of a region of emission nebula lying in the constellation Cassiopeia that is commonly called the 'Fish Head' nebula, part of the larger 'Heart Nebula'. The image was taken through narrowband filters--filters that allow only a thin band of light at very specific wavelengths to pass through to the digital camera. Three filters were used in the image: H-alpha (hydrogen, 656 nm), OIII (doubly ionized oxygen, 500 nm) and SII (singly ionized sulfer, 671/673 nm). The resulting image from each filter is then assigned a color channel to make the final, color image. While the color pallete is somewhat arbitrary, chosen for aesthetic reasons--the colors here are what is commonly called the "modified Hubble pallete" (red = SII; green = Halpha; blue = OIII).

The larger Nebula can be seen here: