John Carmichael wrote:
Hello all:
My new dial design will have the customary seven declination lines
indicating the cusp of each month (the ascent and descent of the sun between
the solstices).
snip
Thanks,
John Carmichael
p.s. I think it would be easier for the general
Patrick Powers wrote:
Use of the moon's motion came later because the moon's motion is so
complex - indeed the main competition to Harrison's clocks in the 1700s
came from the lunar tables that had by then been calculated.
Complementing Patrick Powers' comments:
It took Harrison 40
Jim Morrison wrote:
The attempt by the Spaniards to find
the longitude of Mexico City was done on September 26/27, 1577. Observers
in Madrid and Mexico City both observed the end of a total lunar eclipse.
The value they came up with was 94.5 degrees longitude difference between
Madrid and
Dear Fer:
Thanks for getting back to me. But I still have just a couple of clarifying
questions on the subject.
You use 7 lines for 12 dates. In that case I suggest to use the series
0, +/- 11* 29', +/- 20* 20', +/- 23* 27' for these lines.
I myself often use 0, 11.5, 20 and 23.44 degrees.
Thus
