Montag, 15. Februar 2016

Debunking Dubay 70-79/200

#70 False claim
The distances from Washington Rock are roughly 40 km to Manhattan Island and 80 km to Philadelphia (and not "120 miles").

Looking out from Washington Rock however, you can only look in one direction, which is southeast. Neither New York (NE) nor Philadelphia (SW) lie in this direction.

Let's run the math anyway. Elevation is roughly 510 feet (155m) and not 400 feet. Even if it was in that direction and using the calculation from  #69, Manhattan should be perfectly visible from that vantage point (horizon at 45km).

The drop from the horizon to Philadelphia is roughly an extra 100m. With Philadelphia at 12m elevation, even buildings higher than 88m in Philadelphia should be visible. Factoring in refraction (depending on weather conditions), you would be able to see even more. A rough guessing value for refraction under normal conditions is 0.13 times the expected total drop as seen from sea-level:

Total drop for 80km distance (from sea-level) is roundabout 500m. So that gives you an extra 65m through refraction (with minimum standard value). That means, even buildings in Philadelphia that are only 23m high should come into view under average conditions.

Again, and just in case you're interested, here's a recent study that explains why the refraction coefficient (k)  can be far higher than the standard +0.13, even up to +16 near the ground on hot summer days:

#71 Phony numbers + refraction
On his facebook page, the photographer says that he's taking these pictures from the top of a dune at Warren Dunes State Park on the shore of Lake Michigan. The distance from there to the Chicago skyline is 53 miles (not 60), so roughly 85km. The highest dune in this park stands 73m above Lake Michigan, let's make it 75m from a photographers perspective:
Lake Point Tower is 197m high, less than half the size of Sears Tower. From what I can see in the pictures, we can add a few meters because it's ground level is slightly above the lake. Let's make it 200m.
85km distance accounts for a curvature drop (as seen from sealevel) of 570m. A standard and minimum refraction for this distance is this value multiplied with the refraction coefficient k=0.13. That gives you an extra 74m. Putting them on top of Lake Point Tower gives us 274m (still not even Sears Tower level).

Punch in the numbers (see sources at #69) and you get an added distance of 59.2+30.7= 89.9 km. Because the distance between the two points is 85km it means that the sight lines have to intersect. The tower must clearly be visible and for Sears Tower you wouldn't even have to factor in refraction in order to make this work.

There's also a time-lapse video available on the photographer's facebook page. At the end, you can clearly see refraction going on: 

#72 Very phony numbers
The distance from the riverside of Hull to Grimsby Dock Tower is no more than 15.5 miles (not 70!), so roughly 25km.
The height of Grimsby Dock Tower of 94m alone, leaving out other factors like ground level elevation and refraction, accounts for a horizon distance of 34.6km from the tower.

#73 Refraction
If the numbers are actually correct (impossible to factcheck), a distance of 75 miles (120km) accounts for a curvature drop of 1.13km. Factoring in minimal refraction (sources and calculations see #69&70) gives an extra 150m.
St. Helena is 823m above sealevel (+ 150m refraction), for the ship let's take a crow's nest of 10m height. Add it up and you get 111.4+11.3 = 122.7km. That means it's visible even under minimal refraction influence.

#74 Very phony numbers
The cited 70 feet above sea-level are clearly nonsense when you look at the source of an Italian youtube-video. These pictures must have been taken from one of the tallest buildings or highest points of observation in or around Genoa.

One seems to have been shot from one of the mountains surrounding Genoa.
There's even one scene where you can see a small airplane fly by BELOW the observer.
Monte Fasce just outside the central city is 834 meters high

Here are the coordinates of the building in the first picture: 44°24'16.44"N   8°56'9.37"E.
It's Terrazza Martini Tower, 116m high and standing on roughly 20m ground elevation (according to google earth). The observer is clearly standing higher than that.

Since the 70 feet (21m!) are so utterly misleading and you can't tell the distances from the video, for all following pictures from Genoa I'll calculate with 300m height.

(Sources for calculations: See #69&70)
Gorgona has an elevation of 254m, with 300m observing height in Genoa and refraction coefficient of 0.2 (this is a generous guess for these kinds of conditions) at a distance of 131km you get 143.7km of added intersecting sight lines. Gorgona is visible.

#75 Very phony numbers
See #74 for details.
Monte Cinto on Corsica has an elevation of 2706m. With 300m observation height in Genoa and and refraction coefficient of 0.2 at a distance of 159km you get 260.8 km of added intersecting sight lines. Corsica is very visible.

#76 Very phony numbers
See #74 for details.
Monte Castello on Capraia has an elevation of 447m. With 300m observation height in Genoa and and refraction coefficient of 0.2 at a distance of 164km you get 170.9 km of added intersecting sight lines. Capraia is visible.

#77 Very phony numbers
See #74 for details.
Monte Capanne on Elba has an elevation of 1019m. With 300m observation height in Genoa and and refraction coefficient of 0.2 at a distance of 201km you get 207.1 km of added intersecting sight lines. Elba is visible.

#78 False claim.
Mount Foraker has an elevation of 5304m. Distance to Anchorage is 210km. Even factoring out refraction, the horizon for Mount Foraker lies at least at 260km.

#79 False claim
Denali (FKA Mount McKinley) has an elevation of 6190. Distance to Anchorage is 215km. Even factoring out refraction, the horizon for Denali lies at least at 281km.

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