Allen, I'm serious here. Take your top diagram and your bottom diagram... on each one, collapse the baseline of the annual axis to zero..... You will be left with a diagram of the earth that demonstrates only the nightly star trails in both cases. You have said the baseline should make no difference and that it is essentially zero.... so include that in your drawing and then show me how you'll ever record an annual trail with a camera that is fixed to the earth ? JA... --------------------------------- Get easy, one-click access to your favorites. Make Yahoo! your homepage.