Highspeed Narrowband Filter are designed especially for the delicate requirements of extremely fast astrograph optics, in particular Hyperstar and Celestron RASA telescopes. These sets are available in the folowing sizes:
- 1.25" mounted
- 2" mounted
- 31mm unmounted
- 50.4mm unmounted round
- 50x50mm square unmounted
Conventional narrowband filters cause a heavy loss in transmission due to the strong CWL-shift. In extreme cases the CWL even does shift out of the FWHM (CWL= Center-wavelength / FWHM= full width half maximum). Therefore these filters have a CWL-preshift which matches f/2 to f/3 perfectly.
In spite of the typical line broadening with such fast optical trains they are able to deliver maximum contrast. For the first time these filters allow to use fast optics really effectively with high contrast emission nebulae imaging. Using these filters between f/1,8 and f/3,5 shows a dramatic improvement compared to any regular set of narrowband-filters.
||multiple bands (see spectral image)
|FILTER THICKNESS (WITHOUT CELL)
||2 mm (3mm 50x4/50x50mm)
|CWL (CENTRAL WAVELENGTH)
||656,3 nm;502 nm;673 nm
||dielectrically coated, planeoptically polished
||1.25", 2", 31 mm, 50.4mm round, 50x50mm square
||CCD, Deep Sky, f/2 Highspeed, H-alpha, O-III, S-II
||Mounted (LPFC 6mm) / unmounted
|TYPE OF FILTER
|SINGLE OR SET?
||round & square