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Astrodon Exo-Planet Clear Filter with Blue Blocking - 1.25" Threaded Cell - XOPBB-27R


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

Astrodon created their Exo-Planet filters for the purpose of measuring light curves of planets outside our solar system using typical telescopes an amateur astronomer might possess. While this may seem to be an unreasonable ambition at first, backyard stargazers with sensitive CCD cameras and conventional viewing instruments have the ability to quantitatively measure tiny dips in light intensity as large exoplanets make their way across their suns.

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.

Blocking blue as well as UV light, this filter transmits light from close to 500 nm, which correlates to the traditional V-band filter shape, into the near-infrared region. Gary also states that a “near-infrared filter should be used when observations at low elevations are necessary or when a nearly full moon is above the horizon.” Accordingly, the Astrodon NIR Luminance filter with transmittance from 700 nm into the near-infrared, fits the bill.

As with all Astrodon filters including the LRGB, narrowband, NIR, and photometric models, the ExoPlanet-BB filter is made using a single 3 mm thick substrate to keep refocusing requirements low. Both sides of this filter contain anti-reflective coatings.