Here is the complete stellar spectrograph :-) Note the Cellotape to hold the position of the Baader Blazed Grating so that the spectrum is displayed horizontally within the frame, easily set-up indoors by viewing a tungsten halogen lamp. The Rotating Collar for the lens makes it easy to align the camera with the polar trail of the star you are examining, so that the trailing spreads the spectrum vertically within the camera frame. This enables you to get rid of a lot of noise in post processing (from the Bayer Array and also thermal), as displayed in the previous slide. The available spectral dispersion (the spectral resolution is only slightly worse, depending on how well you have aligned everything) is related to the focal length of the lens used and the pixel-pitch of the camera. With the 100mm Macro lens used here, the dispersion is 3.3 Angstroms per pixel in a Canon 20D, 2.9A/pixel in a 40D and 2.4A/pixel in a 50D. From the result I got on Capella, I estimate that, as used here on a fixed tripod, one should be able to obtain decent spectrograms of stars down to Magnitude 3 at ISO 1600 in 30sec. Not bad for such a simple set-up! Only nuisance was to get the Custom T-thread to 48mm adapter ring fabricated. Why 48mm? It's the same as for astro 2" filters. I suppose I could have used a cardboard ring, or a 1.25" to 2" adapter ring, or perhaps somebody can convince Thomas Baader to include one in his future packages...

Other stuff using this amazing Baader Blazed Grating here: http://www.samirkharusi.net/spectrograph.html