Astrodon Blocking Filters Exoplanet BB 49.7mm Filter, Unmounted

Astrodon introduced the Exoplanet-BB filter for use in amateur-scale telescopes to measure light curves of exoplanets.

Although it may not seem possible at first, astronomers with typical backyard equipment and sensitive CCD cameras have the capability to quantitatively measure small changes in light intensity as large exoplanets pass in front of their suns.

Based upon the extensive work of Bruce Gary in his book, Exoplanet Observing for Amateurs, Chapter 7 concludes that a “clear with blue-blocking filter should be the amateur’s default choice for exoplanets”. The Astrodon Exoplanet-BB filter is that filter, where BB stands for “blue blocking”. He concluded that this filter “has most of the high signal-to-noise advantages associated with unfiltered observing, yet it has most of the reduced systematics advantages associated with V-band and R-band observing.

The spectrum of the Astrodon Exoplanet-BB filter: It blocks UV and blue light. It starts transmitting light near 500 nm, corresponding to the shape of the conventional V-band filter and continues to transmit light into the near-infrared.

The filter is 3 mm thick and is thus the same thickness as all Astrodon LRGB, narrowband, NIR and photometric filters for minimal refocusing. It has anti-reflective coatings on both sides.