Baader Ultra-Narrowband H-alpha 3.5nm Filter (Specify Size)

• Precision grade enforced H-alpha filter for f/10 to f/3.5 optical systems
• Opens up the extremely narrow 3,5nm H-alpha world
• This enforced contrast results in even fainter stars, providing more signal of faintest nebulae detail
• Manufacturing such ultra-narrow filter does require extreme coating homogeneity and very high CWL precision, which these filters are designed for. CWL= Center-wavelength / FWHM= full width half maximum.

Baader's New Ultra Narrowband Enforced Filters

These three sizes of Ultra-Narrowband filters open up the extremely narrow H-alpha, O-III, and S-II world. This enforced contrast provides more signal of the faintest nebula detail. Manufacturing such ultra-narrow filters requires extreme coating homogeneity and very high Center Wavelenth Precision, which these filters have been designed for. Designed for use on optical systems from f/10 to f/3.5.

Now available in all popular sizes; 1.25"Mounted, 2" Mounted, 31mm Round, 36mm Round, 50.4mm Round, 50x50 Square, and 65x65mm Square.

NOTE: In general, the H-alpha ultra narrowband filter is not suitable for solar observation. The half-bandwidth of 3.5nm equals 35 angstroms, much wider than needed for high quality solar observation (sub-angstrom). Never use this filter for visual observation of the sun.

1.25"

2"

31mm

36mm

50.4mm

50x50mm

65x65mm