When people say 8" dobs I say 10"! Sure the tube is fatter but it isn't any longer. The reason is that most 8" (20cm) scopes are f/6 (20 x 6 = 120cm focal length) whereas 10" are generally f/5 (25 x 5 = 125cm). So, if you are limited by the length (or width) of your car, they will both get in the same space. The bigger scope will weigh a bit more (not sure of the details) but I fitted a handle to mine and don't find it too much of a hassle. The up side, of course, is light gathering. The ratio is 10^2:8^2 or 100:64. That means the bigger scope gathers 1.56x more light and that translates into more stars, more nebulosity and more galaxies. It also delays the onset of aperture fever
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