All, Here is a new version of the 3d drawing. I show 3 orbits. The center one is with the baseline of yearly rotation (or translation) at zero. The other two orbits are to demonstrate that no matter how far out the yearly orbit is placed, everything is, mechanically, identical to the center. This is why no annual star trail can be recorded that is different than the nightly.... our mechanics of recording are identical. Allen, Your conception and logic are all correct, except for camera position during recording. The camera must maintain the same angle to the axis in question during recording. The camera in all cases under consideration (and in my drawing) still rotate about the nightly axis, therefore it will only record a nightly star trail. In order to record an annual star trail, the camera must rotate about the annual axis.... and to do that you must change the angle of the camera with each photo... but this would work for a fictitious axis too. JA... --------------------------------- Be a better sports nut! Let your teams follow you with Yahoo Mobile. Try it now.