Astrodon 1.25" Clear Filter - Round Mounted

Astrodon 1.25" Clear Filter - Round Mounted
Item # AN-C2-27R
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  • The Astrodon Clear Filter - 1.25" is presented in a round, mounted format.
  • Produces a >97% transmission throughout spectral region.
  • The Astrodon Clear Filter - 1.25" will increase luminance signal by 45% for Kodak Interline CCD's.


Astrodon Clear Filter - 1.25"

Clear (C) filter with no NIR-blocking has >97% transmittance throughout the spectral region, decreasing to only 95% at 400 nm in the blue. The C filter will increase the luminance signal by 45% for Kodak Interline CCDs. If your goal is to bring out magnitude 22 galaxies by combining many long "luminance" exposures, then it may be best to use this C filter (or no filter at all). However, if your goal is to bring out vibrant color in galaxies, these tests suggest that the L filter, matched spectrally to the RGB filters (and included in the LRBG filter set), is a better choice to eliminate the NIR "galaxy glow" contributed by a C filter. This becomes even more important in systems with refractive optics (SCTs, refractors). If you have a refractor or telephoto lens, remember that a C filter also lets in UV. This is why less color-corrected refractors often need "minus violet" filters to eliminate the optical dispersion in the short wavelength region (blue halos around bright stars). An L filter does cut out some of this. For these systems, an L filter is likely to be a better choice.

Astrodon Near-Infrared Tricolor Filters Features

  • 1.25" mounted, 50 mm diameter
  • 3+/-0.05 mm thickness
  • Parfocal with other Astrodon LRGB and Narrowband filters*
  • NIR Luminance (>700 nm)
  • NIR123 (700-800, 800-900, >850 nm)
  • Set of 4 (NIRL123)
  • NIR Luminance sold separately
  • ~1:1:1 for KAF3200ME and similar detectors
Astrodon Product Number: C2-27R
Additional Information

Additional Information

Manufacturer Astrodon
Type of Filter Clear
Filter Usage Imaging
Single or Set? Single Filter
Filter Size 1.25"
Filter Shape Round
Filter Mounted? Mounted
Warranty 5 Year Warranty
Included Items

Included Items

  • Astrodon Clear Filter - 1.25" Round Mounted
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