Filtro Astronomik ASHB2 da 50.8mm

 

The Astronomik H-beta is a filter for visual observation of hydrogen nebulae, 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 Nebula with telescopes of 10" - 12" reaches the realm of possibility.

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" (20 cm) 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-blocking 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-blocking 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
♦ Parfocal with other Astronomik filters
♦ Glass thickness: 1 mm
♦ 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