Luke Coletti wrote: > > Hello Roger, > > Any thoughts on how one should calculate solar coordinates to be most > precise/accurate? Most solar coordinates are computed for the center of > the solar disk, I would like to hear feedback (since I don't believe > this topic has come up yet) on using coordinates based of the solar limb > (instead of the center) to increase both precession and accuracy of the > cast shadow. I await another stimulating thread. > > Best Regards, > > Luke >
Luke, If you use a rod as shadow caster or a hole in a disk to produce a spot of light to read a sundial you have to calculate the coordinates of the center of the sun. We than read the time at the center of the shadowline or at the center of the light spot. If you use an edge of a solid body then perhaps you may use the coordinates of the limb of the sun. But please, have in mind we are dealing with sundials, not with instruments to read a time in parts of a second or minute. Don't forget the history of sundials. How did people the things at their time? In our time we have other instruments to measure time as precisely and accurate as we want. A sundial still has to reflect to the older times and a suntime hour is irregular in length. Even then I can construct precise and accurate dials. Happy dialling, Fer. -- Fer J. de Vries [EMAIL PROTECTED] http://www.iaehv.nl/users/ferdv/ lat. 51:30 N long. 5:30 E
