IDAS 2 Inch Narrowband Filter Set - H-Alpha, O-III, S-II

This filter set can be used with practically all focal ratios due to its special design. The very steep-flanked passband retains its width almost to the maximum passband, which minimizes sensitivity to the oblique incidence of light at fast focal ratios.
Typically, specially matched filters must be used for conventional and extreme aperture ratios. This IDAS filter set, on the other hand, is suitable for almost all telescope types.
For example, you can use camera and filter wheel completely on different telescopes. There is no need to purchase a second filter wheel and filter set.

The transmission is a maximum of 98% and even at f/2 it only drops to about 70%. The half-width varies only by a maximum of 0.2 nm compared to the nominal value. Each filter is measured; the result can be seen in the attached measurement report.

Not only the passband is important, but also the blocking of unwanted wavelengths. All filters reliably block the wavelengths outside the passband, to which modern camera sensors are sensitive.

Scope of Delivery:

• Filterset 2" HSO