Astromania 1.25" O-III Filter - Bundle with

85mm focal length; reduction factor of about 0.5X; depending on spacing; 0.5x focal reducer effectively halves the focal length of a telescope; enabling lower magnification; a wider field of view; and shorter exposure times for astrophotography
2 lenses for better correction: cemented together and coated; black anodized aluminum housing
Mounting threads: 1.25inch filter thread "28.5x0.75MM" on both sides: Threads into eyepieces; camera adapters; and other accessories with standard 1.25inch threads; and can be stacked with additional 1.25inch threaded accessories
1.25 inch O-III Filter greatly enhances contrast during visual observation of gaseous and planetary nebulae in all sky conditions; astrophotographic 1.25 inch filter allows high-contrast imaging even in areas with strong light pollution
Especially useful for large aperture telescopes through which the light of the Moon can be extremely overwhelming; allow just for the double Ionized Oxygen lines between 496nm to 501nm to pass through at 95 percent

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