Hap Griffin Astrocables

If you are comfortable in working around microelectronics and expensive CMOS sensors, you may want to purchase just the replacement filter to modify your own Canon DSLR from any of the instructions that are available on the internet. I am now proudly the North American supplier of premium quality Astrodon Inside DSLR replacement filters made here in the USA. High end CCD imagers are well acquainted with the quality of Astrodon filters. These DSLR filters are the same as the Luminance filters sold for CCD imaging...they block longwave IR and UV energy, but pass visible light and the all important Hydrogen-Alpha energy.

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.

Filter Characteristics

AD300D for EOS 300D, 350D, 10D, 20D, 30D
AD40D for EOS 400D, 450D, 500D, 550D, 1000D, 40D, 50D, 7D
AD5D and AD5DM2 for EOS 5D and 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.

PLEASE NOTE: When doing your own camera modifications, you void any remaining warranty on your camera and you take full responsibility for any damage done during the modification. I will be happy to answer questions via e-mail but cannot be held responsible for any damages. If you do not feel comfortable working on microelectronics and expensive and fragile CMOS sensors, I offer full modification service using quality Astrodon Inside filters.

Description	Price (inc. US shipping)
Part # AD300D For Canon 300D, 350XT, 10D, 20D, and 30D cameras	$125.00
Part # AD 40D For Canon 400XTi, 450XSi, 500D (T1i), 550D (T2i), 1000XS, 40D, 50D, 7D	$105.00
Part # AD 5D For Canon 5D (not the Mark II version)	$135.00
Part # AD 5DM2 For Canon 5D Mark II	$135.00
Priority International Flat Rate Shipping for non-US customers	$12.95