Baader 31.7mm ND Filter OD 0.9

31.7mm ND Filter OD 0.9

For perfect energy management during Lunar and Solar observation. NO reflections. NO stray light. NO ghosting.

Neutral Density (Grey) Filter 1 1/4", multi-coated / OD 0.9 T=12.5% (optically polished)

Planoptically polished with Phantom Coating Group Multi-coatings.

Special Filter Cell:  Baader's special filter cell design offers unique features that enhance their reliability and usability.  Though difficult to produce, the ultra-thin filter cell results in the maximum possible clear aperture, in order to minimize vignetting (1¼" Filter clear aperture is 27mm!, 2" Filter aperture is 45mm).  The special threading has been designed to fit the wide variety of eyepieces and accessories.

Freedom from Ghosts and Halos:  Baader Planetarium's filters have always been halo and ghost free.  Baader balances each dielectric coating stack to avoid the ghosts and annoying halos that plague other manufacturers filters. 

Stackability:  Unlike most other filters, Baader Planetarium  filters are truly designed to be stacked and combined.  This is possible due to the high optical quality and highly efficient anti-reflection multicoatings.  The ability to combine filters opens up many interesting possibilities, permitting  unique spectral characteristics unachievable with any single filter.