ZWO NARROWBAND FILTERS 31mm Ring refractors

refractors

58 mm (minor axis)

The connections of the mount and keypad security lock screws and only one cable runs from the control box to the mount

Comfortable in astronomical observations with Dobsonian telescopes

ZWO NARROWBAND FILTERS 31mm Ring refractorsThese new 31mm narrowband filters are not mounted in a cell and they are designed to fit on the ZWO filter wheels. Narrowband filters enhance the contrast of emission and planetary nebulae. These peculiar nebulae emit light only in specific wavelengths (H; OIII ; SII) and the narrowband filters have the property to reject all light outside these bands. The passing band or "window" of these filters is 7nm wide. Considering that the visible light