Modification of a Canon EOS 20D for Astrophotography

The Modification

I heard the buzz about modifying digital cameras a long time ago. Since my 20D was my only camera at the moment, not willing to risk it, and I didn't feel much for custom white balance I waited before biting the bullet. When a friend Sven De Deyne modified his and I saw the difference with my own eyes I was sold. In the meanwhile I had gained a bit more financial play and decided to buy a second body to modify. Because of accesories I already had and my dislike for the small size of the 350D for daytime use I opted for a second 20D. I quickly managed to find one used, in good condition.

There is little choice in replacement filters and I opted for the Baader filter. It's available through Telescope Service (I'm in not affiliated to them) and I've been a customer there for a while. It had a bit of a longer journey than expected. Friends ordered the filter and it was supposed to be picked up at the ATH in Hückelhoven. It was picked up and a few weeks later it was handed to me. Upon opening the tiny box it turned out to be empty. Not funny. No April Fools, it really arrived empty. We contacted TS right away and they sent a replacement immediatelly. When it arrived the cause of the mix up was evident: the difference in weight between a filled and an empty box is nihil.

Time for the modification. Tutorials are not overly available on the net, but I managed to find a good one for the 20D by Tim Cann. All you need to know is in there, but here are some pictures nonetheless:

Raw Images

Details: Canon 70-200mm f/2.8 L USM at 200mm f/2.8 at ISO 1600 and IDAS LPS-P2 Front Filter. Exposure was 300s for unmodded and 360s for modified. Due to time of year the object was placed much lower on the sky when the images with the modified camera were taken, which should compensate for the difference in exposure.

Processed Images

Just like in the images above there is a difference in exposure, but it is relatively small compared to the difference in quality in both images. Nebulousity is clearly richer in the left image with fainter parts visible and structure more pronounced. Also processing was less hard which resulted in less visible noise. Due to the less intensive processing star colours and forms have also been improved.

Details and larger version	Details and larger version

Conclusion

Modding the camera pays off!