Optolong H-Alpha FWHM 12nm Filter 1.25" (32mm). HALPHA12NM125
The H-Alpha 12nm filter is a popular narrow-band filter allowing 12nm bandwidth of light with a central wavelength (CWL) of 656nm. It reduces the transmission of certain wavelengths of light, specifically those produced by artificial light. This would include mercury vapor, both high and low pressure sodium vapor lights, and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow). The narrow-band H-alpha astrophotography filter reveals subtle nebula detail at a very high contrast. Main Use and Performance • Suitable for viewing faint emission nebula in the H-Alpha line with full moonlight or severe light pollution. • Hubble look of images can be made by the combination of H-alpha, OIII-CCD and SII-CCD, such as the famous “Pillars of Creation” (M16 Eagle Nebula). • Narrow-band imaging with SHO set (H-alpha, OIII-CCD and SII-CCD) can be done with the moon up in heavy light pollution, so your equipment is not sitting dormant for several weeks. • H-alpha filters are the first narrow-band addition to LRGB set for most imagers who blend a black-and-white Ha image into RGB data to enhance structural detail while maintaining natural look. • Narrow-band filters do not eliminate the effects of light pollution or increase the object’s brightness. In many cases, they increase the contrast between nebula and the night sky, but do not brighten the nebula. • WARNING: Optolong filters are not designed for sun observation. DO NOT LOOK AT THE SUN WITH AN OPTOLONG FILTER. BLINDNESS could occur if you fail to observe this warning.