A simple test for H-alpha response. The nebula shows up nicely, reasonably even in a single frame. Canon 200mm/2.8L lens wide open at f2.8, autofocused on Jupiter (or was it Alpha Centauri?). Hutech-modified Canon 20D with clear glass over sensor (to retain autofocus capability) and Hutech UV/IR Blocking pop-in filter to prevent star bloat from the Near Infra Red. Piggy-backed on an unguided Losmandy G11. Exposures: 28 x 3 minutes at ISO 800. Calibrated with flats, darks and bias. Conclusions: The G11 tracked well, yield at 90+%, the 200mm/2.8L is very usable wide-open at f2.8. Indeed it does not seem to be worth closing down the aperture with the accompanying light loss unless the tracking is expected to be impeccable and one is also willing to put in the extra hours exposure time. Mind you, if I was going to put in the extra hours, I'd probably prefer to use a 2x tele-extender on this object... Eta Carinae is surrounded by quite a bright region of the Milky Way, making it necessary to suppress the high-density of white stars somewhat in order to make the nebula prominent. In this rendition I employed the R-channel as Luminosity. Endless permutations to try out...