Geotio Wrote:
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> As mentioned previously the horizon towards the
> rising sun at Pella on the date of Alexanders
> bithday is much the same as at Manhattan and
> because the latitude is also very close the
> azimuth towards the setting sun at both sites will
> be very similar .
> There are hills that rise to 1500 m to the north
> west of Pella but the sun never sets that far
> north for them to be taken into consideration and
> they don't impact on the horizon calculation for
> Alexander's birthday . If they did the coincidence
> of the two sites sharing a similar latitude and
> horizon altitude , like so many other places on
> the globe , would be truly scuppered .
There is a mountain to the west with an altitude of 1727 m according to Google Earth in the 299.2 degrees direction. If we compute the geometric Sun altitude taking into account the curvature of the Earth we see it is around 1.32 degrees. This would lead to a Sun azimuth of 298 degrees. The structures at Pella were not aligned to this azimuth, they didn't want to encode this. But there is a 1 degree Sun setting difference on the local horizon between Manhattan and Pella during Alexander's birth.

>
>
> > So my proposition is that the ideal horizon
> was
> > taken into account. The actual horizon might
> also
> > have been taken into account.
>
> There is no such thing as an ideal horizon ,that
> is a euphemism for those who are unaware of
> taking the real horizon into consideration when
> calculating declinations and alignments .It
> happens all the time , people look up sun rise and
> sun set bearings on the web ,not realising that
> these sites can't , and don't take the horizon
> into account .They are merely guides ,that are
> relatively accurate as most large cities tend to
> have relatively flat horizons .
This is your opinion. My opinion is that an ideal horizon is useful, and it is used in professional software, so there is no reason to consider it was not used in the past also.






Edited 3 time(s). Last edit at 03/08/2015 05:01PM by Spiros.