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Bring Out The Faint Structures In Nebula
Narrowband filters set a new bar of performance and durability for imaging and research
They enhance contrast of emission targets by lowering your background signal. The guaranteed >90% transmittance at the emission wavelength provides you with the highest signal available. Narrowband filters are renowned for minimizing halos around bright stars, even for long exposures of 30-45 minutes typical of narrowband imaging in astrophotography. Lastly, Narrowband filters are coated to the edge of the part and are edge blackened. This is critical to minimize stray light for a filter that blocks most light except for the narrow bandpass.
Narrowband filters for imaging are all about contrast. What do we mean by this? Contrast brings out faint features by reducing the background – the narrower the filter, the better. The problem is keeping the signal (%T at the emission line) constant as the filter becomes spectrally narrower. This is why our >90%T guarantee is so important, even though it becomes very costly to manufacture. But, this assures you that you can take advantage of the improved contrast with our narrower filters compared to the much less expensive 7- 8.5 nm filters on the market.
You can see the increase in contrast in the sequence of equal-exposure images of the Crescent Nebula (NGC 6888) taken on the same system and on the same night. As the bandwidth becomes narrower, the nebula “pops” out of the background, as does the faint surrounding nebulosity. Actually, the >90%T is a legacy specification, since new production technologies employed over the past 3-4 years routinely produces 97-98%T at the emission wavelengths.
Suitability
- Visual observation (dark skies): Very good, huge contrast enhancement at O III-emission nebulas
- Visual observation (urban skies): Very good, huge contrast enhancement at O III-emission nebulas
- Film photography: It depends, very long exposure time
- CCD photography: Good, when used with an additional IR-block-filter
- DSLR photography (original): Very good, huge contrast enhancement at O III-emission nebulas
- DSLR photography (astro modified): Very good, huge contrast enhancement at O III-emission nebulas
- DSLR photography (MC modified): Good, when used with an additional IR-block-filter
- Webcam / Video (Planets): Unsuitable
- Webcam / Video (Deep Sky): Reasonable, if light pollution is a big problem and OIII Objects are beeing observed
Technical Data
- typ. 95% transmission at 496nm (OIII)
- typ. 95% transmission at 501nm (OIII)
- Complete blocking of all disturbing wavelength coverages
- The ideal filter for telescopes 10 ” (25cm) and larger
- Main operational use: Planetary nebulas & super nova remnants
- No moisture-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
