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Syzygies computing and plotting program : new versions


Version 2 : 29 dec 1995

Should be on line on the ftp server about the 3 of january 1996.

A bug in version 1 of "plot.pas" (on line before that date) made a left shift of all curves on the diagrams. The curves were correct but not in good position regarding to the dates on the x axis. The value of the shift (0 to 3 years) depended on the starting date of the plot. Now fixed.

A limitation in version 1 was the maximum number of month for a plot (10000). This gave a maximum time period of 800 years for a plot, but also for a file of syzygies dates. I used dynamic memory allocation for the table of the montly syzygies quality signal, giving a maximum of 32767 month (2730 years).

The plots.pas program now includes the "Schove's dates" plotting. A file of the dates is read ("SCHOVE.TXT"). There must be normally 207 dates. The dates can be plotted along with the other options.

Sunspot cycles, syzygies (raw or filtered) and Schove's dates can be plotted either without sign (normal Wolf numbers) or with the sign (Bracewell's convention). Choice answering 'Y' or 'N' when prompted before each plot.

The filtering of syzygie quality signal can be done with a narrow filter (70 month Hanning window width) or with a wide filter (500 month Hanning window filtering). The second allows to remove almost completely the 11 years or 22 years periods and to see long term modulations. Choice is done answering 'N' or 'W' when prompted.

In the "syzygies.pas" program, at the beginning of the main section, four lines have been added to allow a shift of the syzygies in order to correlate correctly with the "Schove's dates" for the -300 to +400 period. If the boolean variable is set to "false" (normal situation), there is no shift. If the boolean variable is set to "true", Earth's and Venus' angular speeds on their orbit are modified in order to keep the correlation. See faq 8 for complete explanation.


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