Baader 36 mm Round Ultra-Narrowband 3.5, 4 nm CMOS Optimized Filter Set - Ha, OIII, SII

Baader 36 mm Round Ultra-Narrowband 3.5, 4 nm CMOS Optimized Filter Set

This Baader filter set includes ultra-narrowband H-alpha, SII, and OIII filters especially designed for CMOS cameras. Compatible with both CCD and CMOS technologies, these Baader filters are designed to substantially reduce haloing when used in a setup that includes a CMOS camera and a coma-corrector, field flattener, or reducer/corrector, allowing for the greatest contrast in even the most light-polluted skies.

H-Alpha 3.5 nm Ultra-Narrowband Filter
This ultra-narrowband filter eliminates all but 3.5 nm of the h-alpha emission line, resulting in extremely high contrast astrophotography, minimizing star size and emphasizing fine nebula detail. The central wavelength of its 3.5 nm bandwidth occurs at 656.3 nm. Such a narrowband filter also suppresses mercury (Hg) and sodium (Na) emission lines, which are main sources of light pollution, making this filter good for use under suboptimal skies.

S-II Singly Ionized Sulfur 4 nm Ultra-Narrowband Filter
The S-II singly ionized sulfur filter allows for extreme contrast at an ultra-narrowband of 4 nm. Centered at a wavelength of 671.7 nm, the 4 nm bandwidth is enough to capture singly ionized sulfur emissions at both 671.7 nm and 673 nm common to S-II.

O-III Doubly Ionized Oxygen 4 nm Ultra-Narrowband Filter
The O-III doubly ionized oxygen filter also allows for extreme contrast at an ultra-narrowband of 4 nm, but centered around the O-III emission line of 500.7 nm.

Features:

• Premium grade H-Alpha, O-III, and S-II ultra-narrowband filters

• 3.5 nm-4 nm FWHM for optical systems between f/10 to f/3.5

• Very high contrast even under substantial light pollution

• Reflex-Blocker coating

• Blackened edges

• Optimized for CMOS cameras and also suited for CCD