Optolong H-Alpha7nm Narrowband Introduction

Optolong improved version of H-Alpha 7nm filter is the popular narrowband filter allowing 7nm bandwidth of light centered on a wavelength of 656nm through, and reducing the transmission of certain wavelengths of light, specifically those produced by artificial light including mercury vapor, and both high and low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere.

Main use and performance:

Suitable for viewing on faint emission nebula of H-Alpha line in full moonlight or in 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).

H-alpha filter is the first narrowband 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.

Narrowband filter do not eliminate the effects of light pollution or increase the object’s brightness. In many cases, they increase the contrast between nebula and night sky, not brightening the nebula.

Reference Spectrum