Friday 2010-07-09 Dev. update and Discussion Thread

[Rodolphe]

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Congratulations to the villagers of Ellesborough, Buckinghamshire.

Following the publication of our last friday update, these special guests have received the extreme honour, of becoming exclusive virtual members of the BoBSoWNoSe * community.




Ellesborough Neighbourhood looking southbound :



* BoB SoW North Sector : ))




At 51°N, even during winter solstice, I doubt the sun peeps above the horizon, to the south ??

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[Blackdog_kt]

The earth's ecliptic plane (ie, the plane where the sun's trajectory in relation to the earth lies, if we where to consider the earth as stationary and the sun as moving in relation to it) is near the equator. The equatorial plane doesn't coincide with the ecliptic one because of the tilt in the earth's axis, but it is close.

As such, the sun might move east to west during the day, but its apparent trajectory is always offset towards the equator, regardless of where the observer is standing. What this means is that for an observer in the north hemisphere the sun's apparent trajectory is still an east to west arc across the sky, but this arc is offset to the south. Notice, the arc is offset...the rise and sundown points are still east and west, it's the arc that connects them that exhibits the shift towards the equator. For a southern hemisphere observer it's similar but offset to the north.

Now, i don't know exactly how high the sun should be, or how much to the south the arc of its apparent trajectory lies in the place we see in the screenshots, but there definitely should be a shift to the south in regards to the sun's trajectory across the sky.

Pretty impressive that they model such things if you ask me, as that could hint at more nifty features for the future...night bombing missions and navigating by the stars anyone?

[Tbag]

Rudolphe, how can you be so sure that both images depict the same area?

[Rodolphe]

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Originally Posted by Tbag

Rudolphe, how can you be so sure that both images depict the same area?

Originally Posted by _RAAF_Stupot

How did you figure out that Ellesborough location?

Use Google Earth to compare landscape, river valleys and woods and forests with those depicted on Oleg's screens. You Guys, that's pretty accurate !

Start with the high altitude view than go down to the lower / ground level view.





Sun position issue.


Hypothesis : The observer position alone has moved verticaly. The time is frozen.

On the high level view, check the relation between the Isle of Wight and the west coast of French Contentin and you'll find the sun has a southerly position.

On this ground level screenshot, look at the sun peeping south above the horizon.




Except if the observer lives near Tromsø, at midwinter in the south UK , the sun should rise on a more eastward direction and should get a slightly more westerly sunset.


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[Tbag]

Thanks for the explanation Rudolphe, that makes sense!

[_RAAF_Stupot]

Originally Posted by Rodolphe

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Congratulations to the villagers of Ellesborough, Buckinghamshire.

Following the publication of our last friday update, these special guests have received the extreme honour, of becoming exclusive virtual members of the BoBSoWNoSe * community.




Ellesborough Neighbourhood looking southbound :



* BoB SoW North Sector : ))




At 51°N, even during winter solstice, I doubt the sun peeps above the horizon, to the south ??

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It would, as it is below the arctic circle.

How did you figure out that Ellesborough location?

I think you are right about the location, BTW. You can see a river doing a bend in the screenshots, and if you check on Google maps you can see that the River Thames does that same bend!

It's funny becuase I would have guessed that the screenshots would have been taken from a location much further to the south - but maybe I am forgetting that England really is quite a small place - there is some statistic like no place in England is more than 100 km from the sea....... (or something like that).