Skip to content

Astrodon Clear Filter with UV-Blocking Only - 31 mm Unthreaded Insert - C2-31R

shipping truck Free shipping

About Astrodon UV Blocking Filters

Astrodon filters are high performing, durable filters that provide significant aid for astrophotography and research pursuits. Each filter is constructed using a highly innovative process with a single high quality 3 mm thick fused silica substrate and full hard oxide sputtered coatings. Astrodon UV blocking filters come in two different varieties - a Luminance "L" filter that blocks both UV and NIR, and a Clear "C" filter that only blocks UV. The former is identical to the Luminance filter included with the both the E-Series and I-Series Astrodon LRGB filter sets. This filter provides at least 97% transmission between 400 nm and 700 nm, while the Clear filter provides at least 97% transmission up to 1000 nm.

Astrodon Clear UV Blocked Filter - 31 mm Unthreaded Insert

31 mm unthreaded Clear filter from Astrodon with UV light blocking but no NIR blocking. This filter offers 50% transmission at 395 nm (395 nm cut-on), as well as 97% minimum transmission up to 1000 nm. And, like all filters made by Astrodon, this 31 mm Clear filter is parfocal with every other Astrodon filter, LRGB and Narrowband filters included.

Astrodon 31 mm Clear Filter Highlights

  • Clear 31 mm filter with UV blocking, but no NIR blocking
  • Provides 97% or more transmittance up to 1000 nm
  • 395 nm cut-on (50% transmission at 395 nm)
  • 3 +/-0.025 mm single 1/4 wave fused silica substrate before coating
  • 1/4-wave propagated wavefront before coating
  • Parfocal with all other Astrodon filters
  • Proudly manufactured in the USA