Astronomik H-beta Filter

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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.

Main use

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.

Other uses

• 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.

Suitability

• Visual observation (dark skies): Very good, but only suitable for a few objects
• Visual observation (urban skies): Unsuitable
• Film photography: It depends, very long exposure time
• CCD photography: Good, when used with an additional IR-block-filter
• DSLR photography (original): Very good, but only suitable for a few objects
• DSLR photography (astro modified): Very good, but only suitable for a few objects
• DSLR photography (MC modified): Good, when used with an additional IR-block-filter
• Webcam / Video (Planets): Unsuitable
• Webcam / Video (Deep Sky): Unsuitable

Technical Data

• Transmission of nearly 100% of the H-beta line
• complete blocking of all disturbing wavelengths
• Main operational use: Hydrogen Nebulae
• No moisture (humidity) sensitivity, no aging, and totally scratch-proof
• Excellent carrier material - substrate is optically polished. The optical performance (resolution & contrast) of your telescope is not reduced in any way by the filter.
• Parfocal with other Astronomik filters
• Glass thickness: 1mm
• Completely resistant against high humidity, scratches and aging effects
• Diffraction limited, the filter will not reduce the optical performance of your telescope!
• Astronomik filters are delivered in a high-quality, long lasting, filter box

The filter is available in the following sizes