Useful telescope eyepiece filter transmits 25 percent of incoming light. Ideal for viewing crescent Moon phases and for lunar viewing in smaller-aperture telescopes, for which less dimming is required. We are able to see the Moon at night thanks to sunlight reflecting off its rocky surface. When looking at the Moon through a telescope, bright reflected sunlight can produce significant glare. The Moon's disk, even at partial phases, is in fact so intensely bright with reflected sunlight that observing surface details can be challenging due to the overwhelming glare. This glare can be so bright that it washes out most of the interesting lunar features such as craters, riles, mountains, and valleys. The considerable brightness also reduces contrast on our nearest neighbor in the solar system. When the Moon is in its crescent phase, it does not produce as much glare as when it is full or waxing, but filtration is still recommended to achieve optimal view quality. When looking at the Moon in relatively small (60mm-80mm) telescopes, the brightness is not as distracting as in larger telescopes, but some filtration is required to get the best observations. To improve contrast and tone down glare easily in these situations, we recommend using a neutral-density 1.25 inch Orion 25 percent Transmission Moon Filter. This inexpensive accessory threads directly into a 1.25 inch eyepiece barrel and blocks 75 percent of the light gathered by the telescope, making for more comfortable lunar views exhibiting higher contrast. Once installed on a 1.25 inch telescope eyepiece, the Orion 25 percent Transmission Moon Filter will bring out considerably more lunar surface details thanks to the boosted contrast. Not only will more surface features and details pop out, but you can study them in greater comfort, thanks to Moon Filter reducing overall brightness without altering color.