Spiros Wrote:
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> Construction of Khufu's pyramid started at about
> 2580 BC. Let's thus station ourselves at Manhattan
> - 42nd street and 6th avenue at 2580 BC.

Just noticed this .
Why mention the building of a monument at Giza at a particular date then shift attention to another site 9,000 km away when there was no building going on there that we are aware of , at that date ??
>
> We need to chose the date. The Summer Solstice is
> a pretty good choice. That year the summer
> solstice was on July 15. We consider an ideal
> horizon ,in other words we measure the azimuth of
> the Sun rising on July 15, 2580 BC, at New York
> when it's altitude is exactly zero (0) degrees.

There is no such thing as an "ideal" horizon in astronomy , there are only real horizons .it is only ideal , i.e. convenient to those who are unaware of , can't calculate the real horizon or find it useful to keep it zero suit some agenda .


Heliopolis therefore
> symbolizes the observation of Helios - the Sun
> from New York - at Summer Solstice,

No it doesn't .Heliopolis is where the sun was worshipped ,it bears no relation to a swamp in northern America . If you take the nonsensical 0 altitude from Heliopolis at summer solstice in 2580 bc and , equally nonsensically , extend the line of the sun set azimuth from Heliopolis ,it crosses Cuba and the closest it gets to Manhattan is nearly a thousand miles to the south .
Fwiw the bearing from Heliopolis at summer solstice sun rise in 2580 bc “leads “ to Shanghai , yet another underwhelming ,coincidental “encoding “ .