Allen D I have to break for sleep. As my last post should only take about two minutes to deal with, I thought you might get bored so here is the next description of my problems. If we can ever get through all this stuff, we might be able to get back to the question I asked about my illustration "ThePlank.png" which was "Why won't both daily and annual star trails be be produced from this setup?". I thought this would be as easy as the basket ball question but I guess I was wrong -- you didn't address it at all. ooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo From Allen Daves Thu Nov 8 19:45:02 2007 ... you: I DON'T UNDERSTAND ANY OF THIS. THE DAILY SET OF TRAILS IS CENTERED ON THE NCP WITH THE RADIUS OF EACH CIRCULAR ARC DEPENDENT UPON THE ANGULAR SEPARATION OF THAT STAR FROM THE GEOGRAPHICAL POLAR AXIS.NO! NO! NO! There is more then one axis each with its own rate of real rotation....... not just two rotations on the same axis! You don't seem to grasp the basic mechanic of the whole thing.. or even worse the differnece between those two.......THE ANNUAL SET OF TRAILS IS CENTERED ON THE NEP WITH THE RADIUS OF EACH ARC DEPENDENT UPON THE ANGULAR SEPARATION OF THAT STAR FROM THE ECLIPTIC POLAR AXIS. DEPENDING UPON THE WIDTH FIELD OF VIEW, MANY STARS MAY MAKE TRAILS IN EACH PHOTO RECORD From "9 inverse colours.jpg" We know this path exists, it is in rotation about Polaris. The further the star is away from the axis of rotation the larger the circle path will be. How do you reconcile this with your "NO! NO! NO! ..." statement above? Also, I very carefully structured those two sentences above so as to describe the two axes. You inserted your statement of denial right in the middle of these two sentences. The statement goes on to say "....... not just two rotations on the same axis! " Just where did you get the impossible idea that I think that there are two rotations on the same axis? By the way axes do not rotate -- objects rotate on them. You see, your text and illustrations are riddled with this kind of ambiguity, conflict and error. If you want to communicate effectively ... well I really don't know what you can do but I'll keep trying anyway. ooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo Paul D National Bingo Night. Play along for the chance to win $10,000 every week. Download your gamecard now at Yahoo!7 TV. http://au.blogs.yahoo.com/national-bingo-night/