The Explore Scientific O-III Nebula 2" filter is a telescope accessory designed for observing nebulae. One of the most significant obstacles to exploring the night sky is the brightness caused by artificial lights, such as street lights. The sky is not truly dark near cities, which significantly reduces the visibility of objects outside the solar system. Depending on the type of celestial object, it is possible to drastically increase contrast by blocking annoying artificial light.

The Explore Scientific O-III filter takes advantage of a characteristic property of so-called emission nebulae. These objects glow in special colors called emission lines, which are associated with chemical elements—in this case, oxygen. The Explore Scientific O-III filter blocks all other colors (and thus almost all artificial light), allowing only the two oxygen emission lines to pass through.

The result is impressive: nebulae suddenly become visible in locations that appeared completely empty without filters. For example, under suburban skies, the Veil Nebula NGC 6992 is almost invisible with a 200mm telescope. By using this filter, you can clearly see the nebula and its structures. An essential accessory for every observer.

• High-quality Explore Scientific O-III filter
• Allows only the emission lines of oxygen to pass through
• Absorbs all other emission lines and almost all artificial light

Specifications:

• Type: O-III
• Optical material: optical glass
• Optical coating: multi-coating
• Optical tube diameter: 2” (50.8mm)
• Application: nebula observation