Baader Ultra-Narrowband 3.5nm H-alpha Filter
 Baader Ultra-Narrowband 3.5nm H-alpha FilterBaader Ultra-Narrowband 3.5nm H-alpha Filter 

Baader Ultra-Narrowband 3.5nm H-alpha Filter

  (1 Review)
✓ 2 year warranty


Out of stock due 30-40 working days

About this product

Model:  baader_enf_ha_fltr_2inch
Part Number:  2459454

Baader Ultra-Narrowband 3.5nm H-alpha Filters are precision grade for f/10 to f/3.5 optical systems.

Designed for imaging the extremely narrow 3.5nm H-alpha band. The enforced contrast results in much fainter stars providing more signal in the fainter nebula details with the central wavelength of the filter being 656.3nm.

The manufacture of such ultra-narrow filters requires extreme coating homogeneity and very high center-wavelength (CWL) precision. Each filter is planeoptically polished and hard coated.

Filter sizes available:

  • 1.25"  (2mm glass thickness)
  • 31mm unmounted (2mm glass thickness)
  • 36mm unmounted (2mm glass thickness)
  • 2" mounted (2mm glass thickness)
  • 50.4mm round (2mm glass thickness)
  • 50x50mm square (2mm glass thickness)
  • 65x65mm square (2mm glass thickness)

Important: These filters are intended only for imaging use. They are not suitable for any form of solar filtration. Please see our solar filter section for filters designed specifically for safe solar use.


Below is the real filter-spectrum, taken with an MPI-DADOS-Spectrograph. Comparision with the solar-spectrum (including solar absorption lines).


Customer reviews

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Filter received wiht no markings on the 1.25" barrel.
Thursday, 18 February 2021  | 

I received the filter in a timely manner and well packed and came sealed with the Baader laber over the clear plastic case.

However when I opened it there was no markings on the barrel of the 1.25" mounted filter.
I hope it is the right filter because that is a major quality defect. Also if I ever wanted to resell the filter its value is diminished and some buyers will not even consider it .


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