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Astrodon Exo-Planet Clear Filter with Blue Blocking - 49.7 mm Round Unmounted - XOPBB-50R

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About Astrodon ExoPlanet 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. Astronomers using typical amateur grade backyard telescopes and sensitive CCD cameras can now measure the miniscule decreases in light emitted by suns of other solar systems as large extrasolar planets pass in front of them with this Astrodon ExoPlanet filter with blue blocking.

Astrodon ExoPlanet Clear Filter with Blue Blocking

Developed for the intended purpose of measuring planetary light curves for planets orbiting other stars, this Astrodon Exo-Planet filter works with common amateur-class telescopes. Initially, this would not appear to be possible. But the combination of typical backyard viewing instruments coupled with sensitive CCD cameras provides the ability to assess minute decreases in light intensity emitted by other stars when large planets pass between them and Earth.

The design of the Astrodon Exo-Planet Light Curve Filter is based on the comprehensive research performed by Bruce Gary for his book, "Exoplanet Observing for Amateurs." In this book, Gary concludes that the default filter choice for astronomers wishing to view exoplanets should be a clear filter with blue blocking due to its high signal-to-noise ratio coupled with most of the reduced systematics benefits associated with V and R band viewing. This filter is recommended for observing transiting extrasolar planets with more than 10th magnitude brightness with telescopes at least 16 inches in diameter. With this clear blue blocking filter, reference stars that don't share the same color as the target star won't generate irritating air mass curvatures in the light curve. In addition, most moonlight will also be blocked by this filter for better signal-to-noise. Lastly, lower atmospheric extinction is demonstrated in observations using the Astrodon ExoPlanet-BB filter.

This filter offers light transmittance from near 500 nm, equivalent to conventional V-band filters, up to near-infrared. It blocks both UV and blue light. According to Gary, a “near-infrared filter should be used when observations at low elevations are necessary or when a nearly full moon is above the horizon.” Astrodon's 700 nm to near-infrared transmittance NIR Luminance filter suits this purpose.

Featuring anti-reflective coatings on each side, Astrodon ExoPlanet-BB filters are constructed using a single substrate 3 mm in thickness to match the thickness of all Astrodon filters including their LRGB, narrowband, NIR, and photometric models to limit the need to refocus.