Hello Franks and all, I assume we are to neglect altitude differences and use the fictional spherical earth model, but just what do we mean by 'the same time'? I would assume that when two or more persons look at their watches, corrected for standard zone time, that they read the same numbers? If so, this would give a larger number of answers as the sun sets in each time zone, it will probably occur some place within it at the same clock time as in fixed places in other time zones. Something like the New Year always starts at midnight, so each time zone has it's own New Year, 24 in total. Since the time zones are so non-uniform, the problem could be quite difficult to solve. But you probably mean at the same GMT or Universal time. Then we have our troubles with synchronizing. Given that light travels at about 11.8 inches in a nanosecond, someone 11.8 feet away would be off by 12 nanoseconds. Still, the problem is a neat one!
Having fun with Sundials! Edley. > Greetings, fellow dialists, > > A little while ago there was a dialling discussion about pairs of places > where the sun rose or set at the same moment. I recall that to solve the > problem a "terminator" programme was called into play. > > There are earlier examples of this question. Around the year 1950 > airline pilots (who still used sextants) sat two successive navigation > examinations, the higher of which was called the First N. In the written > paper a question appeared of the form: > > "Find a day on which the sun sets (altitude 0 deg.) at the same moment > in London and Paris (positions given)." > > This problem caused the pilots much head scratching until it was > realised that this type of question occurred in every paper that was > set. The solution is presumably a simultaneous equation in spherical > trigonometry to discover the sun's declination. > > Would any dialist care to try it? > Frank > 55N 1W > > > > -- > No virus found in this outgoing message. > Checked by AVG Free Edition. > Version: 7.5.472 / Virus Database: 269.9.0/852 - Release Date: 17/06/2007 > 08:23 > > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial >
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