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High Point #11 Yellow Green Filter - 1.25" - 11F1

SKU: HPS-11F1

High Point #11 Yellow Green Filter - 1.25"

This High Point Colored Filter has a Wratten number of #11, which is a yellow-greenish filter with a transmission of 40%. A yellow-green filter darkens the maria on Mars and enhances the the largest gap in Saturn's rings, called the Cassini Division. If you have a telescope with an aperture of 11" or larger, this #11 filter can enhance your view of Neptune and Uranus to a small degree.

Colored filters can be an invaluable aid in lunar and planetary observing. They reduce glare and light scattering, increase contrast through selective filtration, increase definition and resolution, reduce irradiation and lessen eye fatigue.

All of High Point's colored filters are made of high quality, solid plane parallel glass that has been anti-reflection coated to prevent glare and ghosting. They have a full 26mm clear aperture, and are mounted in a black anodized aluminum cell that is threaded on both sides to fit most eyepieces and stack with each other.

Please note that the effectiveness of this filter depends on several factors, including the aperture and focal length of your telescope, the magnification being used, and the seeing conditions at the time. Remember that filters lower the amount of light that reaches your eye. You'll need an aperture of at least 8 inches for dark filters such as the #47 Violet, with only 3% transmission, the #25 Red with just 14% transmission, or the #38A Blue with 17% transmission.