Price range: CHF 465 through CHF 590
Antlia SHO 2.5nm Ultra series filters are made of quartz glass and benefit from precisely controlled coating processes to guarantee optimum performance. Their half-value width (FWHM) is 2.5nm +0.3/-0.1nm, with a transmission efficiency of between 92% and 95% at the center wavelength.
The quartz glass used has a very low coefficient of thermal expansion, with excellent thermal and mechanical properties. Combined with advanced coatings, these filters offer outstanding durability, even under extreme environmental conditions.
Compared with the Pro 3nm series, the filters in the Ultra 2.5nm series provide better transmission of emission lines. The Hα line at 656.3nm reaches ≥95%, the SII lines at 671.6nm/673.1nm ≥95%, and the OIII line at 500.7nm ≥92%. These filters can improve the signal in your images by 20 to 30%. What's more, their narrow bandwidth offers an exceptional signal-to-noise ratio for deep-sky astrophotography.
| Hydrogen-alpha | Sulfur-II | Oxygen-III | |
|---|---|---|---|
| Center wavelength (CWL) | 656.3nm | 671.6nm / 673.1nm | 500.7nm |
| Maximum transmission | ≥95% | ≥95% | ≥92% |
| Out-of-band discharge | ≥OD5 | ||
| Filter thickness | 2mm ±0.05mm | ||
NEVER LOOK AT THE SUN WITH THESE FILTERS - This could result in serious eye damage.
