Not to worry Tony. the O111 HB is a fairly wide band filter, but it's main operation is in the O111 line of the spectrum.
Here is a explanation from the supplier
"Precision Interference Filter for EBAY Astronomers that selectively transmits the Hydrogen beta and Oxygen III emission of Galaxies. Specifically produced for EBAY customers, this filter has had significant development to produce excellent transmission of the Oxygen lines at 496.9 nm, 500.4 nm, as well as the 486 Hydrogen, while attenuating most of the background light from other sources. This is a relatively wide pass band nebula filter. The filter is
Mounted in a standard 48 mm eye piece ring. Specifications follow: Central Wavelength, To pass 494, and 486 to 500.4 nm with typical
90%, as well as > 50% (Typically 50% of 656.3nm; Size, 1.78 +0-.006 inches (45mm);
mounted in 48mm eye piece ring. Thickness 2.1 mm. Filter supplied with actual spectral data."
Quote:
Originally Posted by casstony
Those look like filters that have not met production criteria (ie. passbands too wide) and are being sold at a discount. Or am I reading the graphs wrong?
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