The ATM bug strikes again, so I built this 10" f/5. My first attempt at the Obsession design. I prefer a full upper cage for better shielding of stray light, as you can see from the elongated upper cage. FeatherTouch focuser. Antares finder. The mirror was a RF Royce standard mirror, with a ProtoStar spider and secondary. This mirror was a great performer, it trounced a friends 6" Jaegers refractor on Luna. I bought an Osypowski equatorial platform for this scope. Excellent investment! However, there was a lurking danger I discovered one night while observing Omega Centauri from the Arizona high desert. When an equatorial platform is reset *and* the scope is operating at a low angle of elevation it may be possible for the altitude bearings to slip off of the teflon pads. This is exactly what happened to me, and the primary mirror took a tumble, suffering some scratches. I asked Robert Royce about the performance impact of scratches, and he said given what I told him, negligible. Even so, unsolicited he offered to give me a substantial credit towards a replacement mirror! I accepted the gracious offer, and selected a f/6 replacement. The scope was stretched to accommodate the new mirror. I promised myself that was the *last* time I would do split block connectors. From then on, it was Moonlight connectors all the way! Status: This scope was stolen from the backseat of my car shortly after rebuild in 2003. I had left it there in preparation for a 3AM Mars observing session. Fortunately, my eyepiece case was in the trunk so the loss was not total.