The Astronomik H-beta is a filter for visual observation, in particular with instruments of larger aperture.
It lets the light of the H-beta emission line pass nearly unhindered and blocks the remaining spectral range to the extent that the eye is dark adapted. By the use of the Astronomik H-beta filter, the contrast is increased so strongly, that even the observation of the Horse Head Nebulae with telescopes of 10" - 12" reaches the realm of the possible.
The optimal aperture ratio for the use of the filter is 1:4,5 to 1:6. The range of application extends from 1:3.5 to 1:15. Transmission losses and chromatic distortions, which arise with other filters, are only apparent with the Astronomik filters when extremely fast aperture ratios of 1:3 and higher are used. The Astronomik H-beta filter will allow you to view large objects, in the whole field of view of the eyepiece, even when using wide-angle eyepieces - not only in the center of the eyepiece. This filter should be used on telescopes with a diameter of 8 " (20cm) or larger. Smaller instruments do not gather enough light for meaningful and satisfying astronomical work. Due to the high optical quality of the Astronomik H-beta filter substrate you will see the same needle-sharp stars as you would from your regular telescope.
- In the whole sky, there are few objects that benefit from the use of this filter in visual observation. On the other hand h-beta filters often decide about seeing or not seeing an object. Without a filter the eye is hardly able to discover the low contrasts of H-alpha regions.
- With EOS Clip Filter even in extreme light polluted areas photography with DSLR cameras becomes possible.