Explore Scientific Filters 2" OIII filter

• The Explore Scientific 2 inch O III fog filter allows only the emission lines of oxygen to pass.
• The filter blocks all other colours of emission mist and thus blocks almost all artificial light.
• This leads to the fact that the fog becomes visible in places that previously appear completely empty.
• Thread: 2 inches
• Box contents: 1 x 2 inch O III Beta fog filter

In addition to air unrest, brightening the night sky is the biggest obstacle to observing faint objects beyond the solar system. Due to street lamps and other artificial lighting, the sky in human settlements is no longer really black. This also affects the contrast and thus the perception of the deep sky objects. Depending on the type of celestial object, however, you can filter away some of the disturbing light, making it easier to observe the objects. The Explore Scientific O-III filter uses the properties of the so-called emission mist. These objects shine in certain colours, the so-called emission lines. The emission lines are linked to certain chemical elements - in this case oxygen. The Explore Scientific O-III fog filter blocks all other colours (and thus almost all artificial light), and allows only the two emission lines of oxygen through. The effect is amazing: suddenly fog becomes visible in places that appear completely empty without a filter. In the case of slightly brightened skies, for example, the cirrus nebula NGC 6992 is practically invisible with a 200 mm telescope. When using this filter, you can see the mist as well as its structures completely without problems. A must have for any visual amateur astronomer. The Explore Scientific fog filters come with an individual test report - so you can be sure to receive high-quality filters.