Spiros Wrote:
-------------------------------------------------------
> Geotio Wrote:
> --------------------------------------------------
> -----
> > 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 times. Last edit at 03/08/15 11:01AM by
> Spiros.

An "ideal horizon " is not a term used in any form of astronomy , you made it up .
There is the actual horizon , and any one who decides to ignore the real horizon and substitute it with a zero horizon is only confusing themselves .
This mistaken ideakl horizon is not "used " in software ,astro software doesn't know horizons of any site ,it is expected that the at the user does and they can then calculate azimurths etc from that that information .
There is every reason to consider it wasn't used in the past .Provide one example from the annals of astronomy where it was . What possible use would it have been ? As asked earlier but avoided , "How would it have been calculated ?"