Astronomy

The f/2 Ultra-Highspeed series of filters offer line filters with a very narrow full width at half maximum for extremely fast optical systems with an aperture ratio of f/3.4 to f/1.8, such as Celestron's RASA astrograph.

The narrow full width at half maximum allows maximum contrast even in severe light pollution conditions, minimising star size and making the finest nebula details accessible – indispensable under Bortle class 9/8/7/(6) skies.