Astrodon

 

 

Use your Canon DSLR for Daylight AND Astrophotography with Astrodon Inside Premium Replacement Filters

 

Incredible advancements in miniaturization,   computers, data storage, and detector technology have placed affordable, professional-quality cameras in the hands of millions.  This also provides the opportunity for budding astrophotographers to point their DSLR cameras to the night sky and take pictures of galaxies and nebula. Astrodon Inside filter technology was designed for you. 

 

This beautiful image of the Cone Nebula was taken with a cooled, monochrome CCD camera designed for astrophotography. It cannot be used for daylight photography and costs over $10,000 (US).

The DSLR camera provides the means for hobbyists to affordably enjoy astrophotography, but there is a catch.   DSLR cameras were designed for daylight use. They were not designed to easily pick up the rich red colors common to astronomical objects. This deep red light comes from the excitation of hydrogen atoms in space at 656 nm.  We call this hydrogen-alpha, or H-a light.

Canon and other cameras have an internal filter to provide good daylight color balance, but this filter decreases the sensitivity to H-a light to about 20%.  This low red sensitivity makes astrophotography with stock DSLRs problematic. 

Therefore Astrodon provides a replacement filter for Canon DSLR cameras that regains H-a sensitivity to 99% - about a factor of 5 improvement in sensitivity.  The original Canon filter (below left) has a blue-green color, whereas the Astrodon Inside replacement (below right) is totally clear, yet it also blocks all UV and near-Infrared light.

You can see the difference in the following graph, where the transmission of light through each filter as a function of wavelength is compared.

You can see that the Canon filter passes only 20% of the H-a light to the sensor whereas the Astrodon Inside passes~99%. You can also see that the Astrodon Inside filter blocks all UV and Near-IR light.  In the Near-IR, we only transmit 0.003%, whereas a competitor's filter lets 6% Near-IR light pass to the sensor. That's 2000 times less for the Astrodon Inside filter.  We used the Canon filter spectrum from this reference.

The Canon filter must be removed and replaced by the Astrodon Inside filter. For daylight use, you will use a custom white point, often shot with an 18% gray card.  Thus, the modification allows you to enjoy daylight photography while using your Canon camera at night for astrophotography. 

Astrodon has teamed with two expert groups to provide this service; one in North America (Imaging Infinity) and one in Europe (EOS for Astro).  Please contact these experts for the Astrodon Inside modification. Their contact information is shown in the right column of this page.  Astrodon currently does not sell these filters directly.

Filter Characteristics

• AD300D for EOS 300D, 350D, 10D, 20D, 30D
• AD40D for EOS 400D, 450D, 500D, 550D, 1000D, 40D, 50D, 7D
• AD5D for EOS 5D
• AD5DM2 for EOS 5D Mark II
• Use your Canon EOS for daylight AND astrophotography
• Increase the H-a sensitivity by 5x to ~99%
• We use the highest quality, straie-free, fused silica substrates for distortion-free images
• Our substrates have 1/4 wave transmitted wavefront or better prior to coating
• Rigorous filter thickness control for proper EOS focusing
• 100% coated to the edge of the filter with built-in anti-reflective coatings
• Hard, durable coatings that do not require sealing at the edge
• Thousands are in use as Astrodon's luminance (L) CCD filter
• Blocks UV and Near-IR light to better than 0.003% for no leakage
• You do not need a separate filter to block UV or NIR light on your lens
• Best performance for a replacement filter for your Canon EOS
• Inventory maintained to avoid long waits
• Proudly made in the U.S.A.