Narrow band hydrogen alpha filters greatly increase
the contrast in emission nebula. These objects
emit H-Alpha light, having a wavelength of
656.3 nm (Red light). I use a 6nm Ha
filter, which basically allows wavelengths of 653 to
659 to pass. Everything else is filtered out,
including city light pollution and moonlight.
Most of the data, for the images on this page, were taken
when the moon was very bright. Although the
images are simple black and white, I find them
pleasing in a more artistic sense.