iOptron SII 1.25″ Filters

Discover what lurks in the deepest mists
The iOptron SII 1.25″ filter allows you to see details that would otherwise remain hidden. This filter is specially designed to capture the light of ionized sulfur - the glowing red light emitted by many planetary nebulae and supernova remnants. Thus, you bring contrast, texture and depth to your astrophotos that are simply lost with ordinary filters.

Narrowband filter with maximum precision
The filter lets light through only at 672 nanometers, with a bandwidth of only 7 nanometers. Everything beyond that is effectively blocked. That means: clean images, minimal light pollution and greater visibility of the finest nebular structures. Perfect for nights when every photon counts.

Ideal for Hubble-style image combinations
Use the SII filter together with H-alpha and OIII filters for impressive narrowband shots. By combining these three channels, you'll create images full of color and depth - with subtle reds that show off the sulfur nebulae beautifully. This gives you results reminiscent of professional astrophotos.

Built for long-term performance
The aluminum mount is sturdy and lightweight, so the filter fits securely in any 1.25″ mount. The multiple coating prevents reflections and unwanted halos, keeping your shots clear and contrasty, even at long exposure times.

For those who want to see beyond visible light
The iOptron SII 1.25″ is perfect for astrophotographers who want more than standard shots. Ideal for capturing emission nebulae with fine detail and natural glow - and for taking your deep-sky images to the next level.

Specifications

Capacity

Optics

General

Observation goals