iOptron SHO Narrowband Filter 1.25"
Information for HA:
iOptron H-Alpha 7nm filter is the popular narrowband filter allowing 7nm bandwidth of light centered on a wavelength of 656nm through, and reducing the transmission of certain wavelengths of light, specifically those produced by artificial light including mercury vapor, and both high and low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow). Better choice of narrowband H-alpha astrophotography filter for highest contrast and revealing subtle nebula details.
H-alpha filter is the first narrowband addition to LRGB set for most imagers who blend a black-and-white Ha image into RGB data to enhance structural detail while maintaining natural look.
Narrowband filter do not eliminate the effects of light pollution or increase the object’s brightness. In many cases, they increase the contrast between nebula and night sky, not brightening the nebula.
Information for SII:
An improved narrowband SII filter (Sulful II for CCD) is designed for nebula observation. The filter isolates the light at the wavelength of 672nm. It allows it to pass through and reduces the transmission of certain wavelengths of light, specifically those produced by artificial light including mercury vapor, and both high and low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow).
Narrowband filter do not eliminate the effects of light pollution or increase the object’s brightness. In many cases, they increase the contrast between nebula and night sky, not brightening the nebula.
Information for OIII:
An improved narrowband OIII filter is designed for nebula observation. The filter isolates the 500.7 nm and 495.9 nm wavelengths of light. It allows them pass through and reduces the transmission of certain wavelengths of light, specifically those produced by artificial light including mercury vapor, and both high and low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow).
OIII emits 495.9nm and 500.7nm and it is a blue-green colored filter. Many of images of planetary nebula and supernova remnants are taken only with H-alpha and OIII filters. They show great structural details, but have natural colors, looking like an RGB image.
Narrowband filter do not eliminate the effects of light pollution or increase the object’s brightness. In many cases, they increase the contrast between nebula and night sky, not brightening the nebula.
WARNING: iOptron filters are not designed for direct solar observation. NEVER use these filters for observing or imaging the Sun, or permanent eye and equipment damage will result.
Technical Specifications
Information for SHO:
| Parameter |
Value / Requirement |
Notes / Examples |
| Mounted Diameter |
1.25″ |
Compatible with a 1.25″ filter wheel |
| Standard Thread |
M28.5 × 0.6 |
This is the standard thread for 1.25″ filters in astronomy |
| Usable with Eyepiece |
Yes (1.25″ eyepiece) |
The mount is compatible with a 1.25″ eyepiece |
| Coating |
Multi‑layer anti‑reflection |
To maximize transmission |
| Surface Quality (scratch/dig) |
60/40 |
Good optical standard |
| Surface Flatness |
< λ/4 |
To limit aberrations |
| Parallelism |
≤ 30″ (arcseconds) |
Typical value for high‑quality filters |
In the Box
iOptron SII Narrowband Filter -1.25"
or
iOptron OIII Narrowband Filter -1.25"
or
iOptron H-Alpha Narrowband Filter -1.25"
Warranty & Manuals
iOptron Warranty
