In this article, I will describe how I modified a Canon 1000D (Rebel XS) DSLR to become a dedicated astronomical camera, with all functions intact including its auto-focus capabilities, and thus, may still be used for non-astronomical purposes. The camera belongs to a fellow astronomy enthusiast and I was happy to accommodate the request to have it modified. It took me around 2 hours to complete the modification.
Canon 1000D DSLR modified for astrophotography
The modification involves the replacement of the camera’s stock (built-in) filter with a Baader BCF (Baader Conversion Filter). This filter allows greater sensitivity to H-alpha wavelengths emitted by most deep-sky objects, while at the same time eliminate unwanted UV and other IR wavelengths. This filter is necessary for any system that uses lenses in the optical train.
Below are some photos taken during the modification with detailed descriptions of some of the key steps.
Canon 1000D ready for filter modification. Test all functions of the camera to make sure that it is in perfect working order. The battery and the SD card must first be removed.Remove pertinent screws and carefully pry open the camera’s back coverOne at a time, unseat all ribbons connected to the topmost circuit board.Remove the topmost circuit board (right) to gain access to the DSLR’s imaging sensorCarefully remove the circuit board that holds the imaging sensor (this part is called the CMOS assembly)Keep the imaging sensor and the dust-cleaning filter free from dustThe stock filter (left) was then removed from its cell (right) with the help of a sharp cutter blade. In this particular modification, the stock filter was replaced with a Baader Conversion Filter (BCF) and the dust-cleaning filter was retained to preserve the camera’s auto-focus capability. For full-spectrum modification, simply remove this stock filter and remove the dust-cleaning filter (upper left) as well with no filters to replace them both.Camera’s stock filter (left) was then replaced with a Baader Conversion Filter (right). The whole CMOS assembly that holds the sensor, the filter cell (with the BCF), and the dust-cleaning filter was then reassembled.The CMOS assembly and the circuit boards have been reconnected and all ribbons have been reseated. This part must be done with utmost care to avoid short circuits.The camera was then tested. Everything worked fine during power up. All functions of this filter-modified Canon 1000D DSLR camera remain intact, and thus, may still be used for non-astronomical purposes.
Below is a test image taken with the modified camera. More test shots will be posted soon. Clear skies!
Image of the moon taken with the modified Canon 1000D DSLR camera. Note the reddish hue is due to the characteristic of the replacement filter. Photo Credit: James Kevin Ty. Published with permission.
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Job well done! Greatly appreciate your help on the modification. Now to wait for clear skies to test it out.
No worries sir! I look forward to seeing your images :)
Great info, do you have any link or doc to show how to replace the auto focus unit on Xsi/450D?Thanks in advance.
Can you clarify what you meant by replacing the auto-focus unit (which is not covered in this article)? What exactly do you want to do with your 450D?