DayStar Filters is an American manufacturer specializing in high-precision solar observation equipment, particularly narrowband Hydrogen-alpha (H-alpha) filters. These filters isolate a very narrow portion of the solar spectrum (typically around 656.28 nm), allowing amateur and professional astronomers to safely view and image dynamic solar features such as solar prominences, filaments, plages, sunspots, and the chromosphere. These details are invisible in ordinary white-light viewing.

Their popular products include the innovative Quark series (compact “eyepiece” filters that convert small refractors into dedicated solar telescopes), as well as dedicated solar scopes like the Solar Scout and various Quantum models. DayStar filters are known for their optical quality, reliability, and ability to deliver high-contrast views of the ever-changing Sun while blocking harmful ultraviolet and infrared radiation.