Astronomik SII CCD Filter

This filter is designed to isolate the Sulfur II emission line, which is commonly found in many nebulae. By blocking out other wavelengths of light, it allows you to capture high-contrast, detailed images of these deep-sky objects even from locations with significant light pollution.

This is a standard 1.25-inch round mounted filter, which is compatible with most filter wheels and filter drawers designed for that size. If you are using a larger sensor or a camera with a different mounting system, you should verify that your specific filter wheel or drawer accepts 1.25-inch mounted filters.

A 12nm bandwidth is a moderate narrow bandpass that strikes a good balance between signal-to-noise ratio and exposure time. It is narrow enough to effectively cut through light pollution and isolate the Sulfur II signal, but wide enough to allow for shorter exposure times compared to ultra-narrow 3nm or 5nm filters.

No, this filter is specifically engineered for CCD and CMOS astrophotography. It is not intended for visual use, as the human eye is not sensitive to the specific wavelengths this filter isolates, and it will likely appear almost completely opaque when looking through an eyepiece.

The filter is constructed from high-quality optical glass designed to maintain image sharpness across the frame. Astronomik backs this product with a 10-year warranty, which is a strong indicator of the manufacturer's confidence in the filter's resistance to degradation over time.