Baader 1.25" f/2 Highspeed Filter Set
The 1.25-Inch f/2 High-speed Filter Set by Baader Planetarium:
Baader's new f/2 High-speed Narrowband filter sets contain H-alpha, OIII, and SII filters and are made specifically for the sensitive requirements of exceptionally fast astrograph optics, such as HyperStar, RASA, and extremely fast instruments from TEC, AP, ASA, etc. Ordinary narrowband filters generate a heavy loss in transmission because of the strong CWL (center-wavelength) shift. In severe circumstances, the CWL even shifts out of the FWHM (full width half maximum).
As a result, these filters have a CWL-preshift which flawlessly matches f/2 to f/3. Furthermore, the FWHM is enhanced. Despite the typical line broadening with such fast optical trains, these filters are still able to produce peak contrast. These filters permit the effective use of tremendously fast optics for maximum contrast imaging of emission nebulae for the first time. Compared with a regular set of narrowband filters, using these high-speed filters between f/1.8 and f/3.5 will exhibit drastic improvement.
OPT Product Number: BA-FHSS-1