iOptron SII Narrowband Filter -1.25"

Switching to this SII filter from a cheaper one, the 672nm bandpass is noticeably sharper—nebulae in the sulfur channel look way more defined now.

The 672nm isolation on this SII filter really cuts through the background skyglow from my suburban backyard. Stacking just two hours of data on the Bubble Nebula brought out detail I’ve never seen before with my older filter.

I’m finally getting clean SII data in my narrowband stacks—the 672nm isolation made a noticeable difference in cutting through light pollution. The glass is crisp and the threads fit smoothly into my filter wheel.