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Old 12-02-2019, 10:06 AM
Saturnine (Jeff)
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Saturnine is offline
Join Date: Jul 2008
Location: Wollongong
Posts: 610
For starters, I suspect that the flip mirror adds too much length to the imaging train. The simplest way to find out where the focal plane is in the system is to remove the camera and put in an eyepiece and bring that to focus. If focus can't be achieved with an eyepiece with the flip mirror in place, no matter how much the focuser is racked in or out, remove the flip mirror assembly.
With the eyepiece inserted directly into the drawtube again rack the focuser in or out until focus is achieved. once you have focus with an eyepiece, then your ZWO camera will require about another 12 / 15mm of in travel of the drawtube for the camera sensor to reach the focal plane.
Using an barlow will move the focal plane further out, maybe not by much, my 2.5X Powermate when added to the imaging set up requires the drawtube to be racked out an extra 10 / 12mm approx. That is why you can just reach focus with an barlow in place and therefore without an barlow in place you you need some extra in travel of the drawtube to reach focus.
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