Dr. Jones, My replies in red, I do not understand your drawings. You have not changed the rotation axis from one scenario to the other, so the box is just as far away from the axis in both cases. Correct, but does not matter. What I changed was the way the camera moves around the axis, to demontrate the difference between a camera recording nightly trails and a camera recording annual trails. In diagrams 1, 2 and 3, your camera should not be diverging onto the axis, but be parallel with it. As Allen has said, it does not matter what angle the camera is pointed at, as long as you leave it still, it will record a star trail. The difference between different camera angles will determine where the axis is in the picture. Just like you have in 4, 5 and 6, but here you have not changed the axis! If you change the axis so as to point towards the box and make the rotor blades orthogonal to that axis, then what is the difference between the mechanism of 1, 2 and 3, from 4, 5 and 6? I believe I would still record the same event, just the center of rotation would appear in a different place on the film. The difference between the two (1,2,3 & 4,5,6)(I wish I had thought to name these better) is the difference between the stationary camera rotating with the axis which will record a star trail and the not stationary camera rotating against the axis which will not record a star trail. Perhaps you could redo the diagrams and see. I'll see what I can do, to make it clearer. Allen, Allow me to demonstrate. Actually, your mention of the helicopter is what got my confused questioning to gel into something I could better understand, so I have used the helicopter as my device. I found this much easier to visualize and draw the motions. The Helicopters body will represent whatever axis we are considering. The box on the ground beside the helicopter is any star you want to consider a star trail for. The rotor is either the baseline of earths radius or its orbit depending on whether you are talking about the nightly or annual trail. The Camera on the end of the rotor the camera sitting on a tripod anywhere on the earth. Drawings 1, 2, 3 are of the setup of my system to simulate the nightly star circle. The only difference between 1,2&3 is that I am increasing the length of the rotor axis, so that you can see where the circle produced is heading as the distance begins to negate the baseline (rotor length). Drawing 7 shows the positions of the camera as it is swung around the axis. Drawing 9 shows the results (the trail formed by taking a timelapse photo through one revolution in each of the three drawings). The circle is progressively moving to center on the axis of rotation. Exactly what we see in the sky and what your model predicts. Drawings 4, 5, 6 are of the setup of my system to simulate the annual star circle. The only difference between 4,5&6 is that I am increasing the length of the rotor axis, so that you can see where the circle produced is heading as the distance becomes more important than the baseline (rotor length). Drawing 7 shows the positions of the camera as it is swung around the axis. Drawing 8 shows the results (the trail formed by taking a timelapse photo through one revolution in each of the three drawings). Both circles (the axis circle and the box circle) are decreasing in size and will diapear into a dot with enough distance. Exactly what we see in the sky, but not what you are predicting. So what is different in my model to yours? If your camera takes pictures 24 hours apart, you are not taking into consideration that the camera has not rotated with the axis of rotation you are trying to record, and as my model shows, that is all the difference needed to make the annual trails disapear. This is not a proof of HC, only a disproof of the disproof, which are not the same. JA... --------------------------------- Free 3D Marine Aquarium Screensaver Watch dolphins, sharks & orcas on your desktop! Check it out at www.inbox.com/marineaquarium __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com