The C9.25 will be around 105mm from the sensor to the back of the reducer. It would be checking with Celestron on this as its for an older camera Canon 450d. The asi 224 wont be so critical due to size of the sensor. The Starwave 80mm will be according to the type of 0.8 reducer as they all differ in spacing. So a Skywatcher reducer wont work on all telescopes though they generally say they do.
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