[mental4astro (Alexander)]

Thanks Ken.

One thing first. When you look up the baffle, does everything look co-centric? All the mirrors, reflections, tube outlines, mirror outlines, everything should be co-centric. I want to make sure it is the primary mirror that is out of kilter first before opening up the OTA.

If it is the primary mirror that is out of position, it will mean needing to open the OTA via the rear, removing the back section an inspecting the mirror/focus mechanism. Sounds horrific, but it's more daunting than difficult. There's plenty of info on doing this, including videos. But one thing at a time, and lets look for the tell-tale signs that the primary mirror is out of position on the focuser mechanism. Another way, though more tricky, is to see if the outline of the primary mirror looks co-centric with the rest of the scope when you look down through the corrector plate. May be difficult to gauge this as the primary may just be a few mm out of position. If it is the focus mechanism that out of whack, then we'll look at fixing this.

The primary mirror being out of position may also explain the rubber washer being chewed up as there is a strain on the focuser mechanism that's pushed the driving threads out of whack, and hence drove the rubber washer out when the focuser knob was turned so far.

Alex.