Astronomik H-Beta Filter - 1.25" Round Mounted

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Astronomik H-Beta Filter - 1.25" Round Mounted

Astronomik 1.25" H-Beta Visual Filter

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 to 1:6. 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" (200mm) 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.

Astronomik 1.25" H-Beta Visual Filter Features

  • 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

Additional Information

Filter TypeH Beta
Free ShippingYes
Peak Transmissionalpha
Warranty10 Year Warranty

Questions & Answers

Ask a Question
  • what is the FWHM of this filter (12nM)?

    The FWHM is around 13-15nm based on the bandpass graph that Astronomik publishes for this filter.