On Thu, 15 Jan 2004, John Hall wrote: > Hi Ed > > The answer is yes, and there is an example of how Longitude correction > might be done in 'Practical Astronomy' by H. Robert Mills on page 106 > in the edition I have. To correct for EQT replace the straight hour > lines with analemas and ensure that there is a defined point on the > shadow casting edges to indicate time.
OR, arrange mechanically to rotate the dial plate about an axis parallel to the polar axis, with a cam, scale, or other means, to compensate on a daily basis. Dave 37.277N 121.966W > > On 15/01/2004, at 3:40 AM, Ed Olander wrote: > > > On a properly designed and aligned polar dial, is it possible to > > adjust for > > EOT and longitude correction by rotating the dialplate along the axis > > of its > > gnomon, or is this type of correction only effective on equiangular > > dials, such > > as the equatorial? Will this technique work on horizontal dials as > > well? > > Best regards > > John Hall > 41.5 South 147.1 East -
