Canon Digital Rebel (aka 300D, Kiss Rebel) Digital SLR - modified

An exciting development! I believe the Canon Digital Rebel and other similar digital SLRs are signalling the extinction of film in astrophotography! Using a 6.3 megapixel CMOS sensor, the Rebel allows for full 35mm color images without the need to spend around $9000 for an astronomical CCD camera that gives the same field of view.  At less that $1000, when purchased with the 18mm-55mm zoom lens, the Rebel provides at least 10 minute exposures in bulb setting (limited more by heat noise than shutter ability).  With the trend toward stacking multiple images in processing software, this camera allows for some nice deep sky images, deeper than people might expect. There is a deficiency in hydrogen-alpha sensitivity, but no more so than even the best films.  This is true, especially when you consider that you need much longer exposure lengths with film to give the same amount of the red color in the hydrogen part of the spectrum.  I have modified this particular Rebel by removing the overly-aggressive IR filter that covers the CMOS chip.  Early tests of the modification on this camera can be seen here.  It's obvious that the removal of the IR filter allows for increased red sensitivity, making it a serious astro camera indeed! 

The wonderful thing about digital SLRs like this Canon is that their lenses can be removed, unlike normal "point and shoot" digital cameras.  This means that you can use standard T-mounts to connect digital SLRs to the prime focus of a telescope, not being restricted, as you are with typical digital cameras, by having to connect it to an eyepiece.  This means that the Digital Rebel can be used at the scope's native focal ratio, providings wide fields and shorter exposures of deep sky objects.   The same cannot be said of digital cameras of the "point and shoot" variety.

The Rebel also doubles as a fine terrestial camera, full of features that rival cameras costing much, much more.  It uses EF and EF-S series lenses, which are some of the finest lenses made to date.  For those considering the removal of the IR filter, you need to know that it would make the Rebel unusable for terrestrial work, at least not without adding a replacement filter that isn't as restrictive as the one that comes stock.

In case you are confused by the many names of this camera, this Canon digital SLR is known as the Kiss Rebel in Japan, the 300D in Europe, and the Digital Rebel in the United States.  Regardless of the name, they are exactly the same camera.

The picture above shows the Canon Digital Rebel connected to the prime focus of the Tak FSQ-106.  It can be operated in bulb mode using a special remote shutter cable.  This allows for exposures as long as necessary, at least until the heat noise becomes too objectionable.  "Images Plus" is the preferred software for use with all digital SLRs, allowing for color dark subtraction and registration of several images at once.  The newer release, version 1.72, even has an automated focusing routine.