John, answers in your text.
John Carmichael wrote: > > 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 calculte the lines as declination lines, not as lines of date. > > How were these specific declination values originally determined? Are they > average values taken over many years or are they from a year half way > between two leap years, and if so, which year was used? Starting at 0 Aries with declination 0 degrees the start of each sign will have the same declination during many years. No need to choose an average value over a peoriod of 4 years or a year between 2 leap years. The problem arises when we want to add a date as 21 march and so on. Because we want to use one line for 2 signs just take the average declination for these 2 signs. > > Would you consider the dial pictured opposite page 200 of Mayall to be > correctly labeled for your suggested declinations? I needed a magnifying > glass to read them, but they appear to be: > > Jan. 21, Mar. 21, Apr. 22, May 22, Jun. 21, Jul. 22, Aug. 22, Sep. 23, Oct. > 21, Nov. 21, and Dec. 22. Also feb. 21 is on the dial. > (The designer of this dial includes the declination line for Nov. 1, > presumably to reduce the large spacial gap between the Oct. 22 and Nov. 21 > lines.) I read nov. 5 in stead of nov. 1 Also for the same reason feb. 5 is added. Looking in an almanac for 1999 the start of the signs should be at: jan 20 feb 19 mar 21 apr 20 may 21 jun 21 jul 23 aug 23 sep 23 oct 23 nov 22 dec 22. I didn't check the declinations for these dates. These dates can change at your longitude with one day, depending on the time it real happens. In the almanac I looked the dates and times are for our time zône. Happy dialling, Fer. > > Thanks again Fer, it's comforting to know that these answers are coming from > the horse's mouth himself! > > John Carmichael > http://www.azstarnet.com/~pappas -- Fer J. de Vries [EMAIL PROTECTED] http://www.iaehv.nl/users/ferdv/ lat. 51:30 N long. 5:30 E
