Now you can capture dramatic Hubble-like CCD images of emission nebulas from the heart of the city or under a full Moon. How? By imaging with S-II, O-III, and H-alpha extra-narrowband filters. These specialized filters transmit only the specific wavelengths of light that are important in emission nebulas, while blocking out all other light, whether artificial or natural - from street lamps, the Moon, you name it! The result: high-contrast tricolor images from even grossly light-polluted skies.
The S-II filter passes light at the 672.4 nm wavelength (the Sulfur-II line in the deep red end of the visual spectrum) with very high 90-percent transmission and a bandpass of 7 nm. It complements the Orion H-alpha and Oxygen-III extra-narrowband filters, which together allow advanced tricolor imaging of emission nebulas with the StarShoot Deep Space Monochrome CCD Imaging Camera or other monochrome CCD cameras.
These 1.25-inch filters are made from high-grade glass and feature vacuum-deposited dichroic interference coatings and anti-reflection coatings. All three are parfocal, meaning no refocusing is needed when switching among them. Each filter is held in an anodized aluminum cell that is threaded to fit a standard CCD camera 1.25-inch nosepiece or the Orion Multiple Filter Wheel.
Images taken with extra-narrowband filters typically look much different from those acquired using standard "true color" (RGB) methods. Rather than rendering an image in its natural color, the extra-narrowband filters provide a visual representation of the elemental makeup of a nebula, highlighting with assigned colors the areas where the light derives predominantly from either Sulfur-II, Oxygen-III, or Hydrogen-alpha ions. This is the approach used by astronomers for many of the nebula pictures taken with the Hubble Space Telescope. The extra-narrowband "false color" images, while beautiful, also reveal much about a the chemical composition of the nebula and its various features.
So if you're ready to go beyond RGB imaging and capture your favorite nebulas in a revealing new light - no matter how light-polluted your skies - add the Orion S-II (and O-III and H-alpha) Extra-Narrowband filter to your imaging arsenal! Includes protective plastic case.