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Knowledge Database

This Knowledge Database is a collection of links to websites, videos and papers that support facts like that the earth is a rotating globe, that space and satellites exist, that man landed on the moon and many more.
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Link: walter.bislins.ch/bloge/?page=Knowledge+Database&qs=Curvature&mask=3

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Curvature of the Earth at Bonneville Salt Flats

⇒ www.flickr.com

Overlooking the Bonneville Salt Flats from Wendover, NV.

Curved Horizon drop demonstrated at Night on the Head-up Display

⇒ www.youtube.com

#23 | 6/8/2017 | Author: Wolfie6020 | Type: Youtube | Keywords: Drop, Curved Horizon, Left Right, HUD, EVS, Aircraft, Cockpit, Sunset

Just another video proving the horizon does not always rise to eye level. The drop at 43,000 ft altitude is about 3.6°, as shown on the Head-up display (HUD) of my aircraft. At this night just after sunset the horizon was very clearly visible and matched exactly the horizon of the Enhanced vision system (EVS) of the HUD. We could even clearly see the left to right curvature of the horizon from that altitude.

The Horizon is not at Eye Level. Flying West over water with clear skies
Raw uncut video showing both the drop and curve from 46,000 ft altitude on a clear distinct horizon as seen through a HUD.

Curved Horizon from 46,000 ft through a HUD, CurvApp overlay
Overlay of Curvature App graphic with screenshot from above video. Reality matches the prediction of the Curvature App, based on the globe model, perfectly.

Earth Curvature from 43,000 ft altitude

⇒ www.youtube.com

#4 | 9/27/2016 | Author: Wolfie6020 | Type: Youtube | Keywords: Curvature, Cockpit, High Altitude

This video clearly shows the Horizon curvature I see at high altitude. We fly significantly higher than most commercial aircraft. We operate above 45,000 ft routinely. Airliners operate typically Mid to High 30's. (35,000 to 39,000 ft).

Showing Curvature with an Auto Level

⇒ www.youtube.com

How an Auto Level can be used to measure the horizon drop. Roohif explains how this is done at an observation over water. The measured drop conforms very well with the prediction of the globe model using standard refraction of 7/6 R.

In the second part he shows how an Auto Level is calibrated:

Apparent Curvature of the Horizon vs. Curvature of the Earth

#43 | 4/15/2019 | Author: Rory | Type: Website | Keywords: Apparent, Curvature, Left Right, Horizon, Calculation, Sketch

ZoomImage-InformationsSketch of how to Calculate the apparent Curvature of the Horizon on flat images

Not many people are immediately aware of the difference between the curve of the Earth and the curve of the horizon.

The sketch on the right shows how the apparent curvature of the horizon follows from the perspective transformation onto a flat image. Although the apparent curvature of the horizon on flat images is the result of perspective, its origin is the curvature of the earth.

A projection of the horizon onto a vertical cylinder with the axis at the observer will result in a straight horizon line, that lies parallel below eye level. If the axis of the cylinder is not vertical, the horizon will form a sine wave. The distance of the horizon line from eye level depends on the altitude of the observer.

Left-Right Curved Horizon from 494 m Altitude

⇒ www.youtube.com

#127 | 3/18/2020 | Author: Bobby Shafto | Type: Youtube | Keywords: Curved Horizon, Left Right, Horizon-0-Matic, Image Compression

Using a Horizon-0-Matic (nod to Rory), a 24 mm wide angle lens (no fisheye) with 80° field of view and horizontal image compression we can make the left-right curvature of the horizon visible. Horizontal compression exagerates the curvature of the horizon, if there is any, without curving the straight parts of the Horizon-0-Matic.

Advanced Earth Curvature Calculator

⇒ Advanced Earth Curvature Calculator

#27 | 8/31/2018 | Author: Walter Bislin | Type: Website | Keywords: Calculator, Curvature, Horizon, Hidden, Drop, Perspective, Computer Model

This website calculates horizon and target related values and shows a 3D perspective representation for Globe and Flat Earth of the calculations from the viewpoint of an observer. On the Globe Model it includes an accurate calculation representation of refraction.

Detecting Horizon Curve by Horizontal Compression (4K)

⇒ youtu.be

#196 | 4/3/2021 | Author: Bobby Shafto | Type: Youtube | Keywords: Curvature, Drone, Compression, 4K, Levels

To highlight any lateral "bowing" of the horizon, I squeezed the horizontal dimension to about 20% without constraining the vertical. The placement of two straight-edge carpenter levels is to check to see if the camera lens is responsible for any warping or vertical distortion. But if the levels above and below the angle to the horizon remain straight, then any bowing of the horizon is due to something else other than lens distortion. ~ Bobby Shafto

Approximations for Curvature Drop, Dip, Horizon Distance, Hidden Height

#207 | Author: Walter Bislin | Type: Math | Keywords: Approximation, Equations, Curvature, Drop, Hidden

(1)

Curvature Drop

(2)

Dip Angle

(3)

Horizon Distance

(4)

Hidden Height

where'
' =' 'drop from the horizontal at surface, also known as 8 inches per miles squared
' =' 'dip angle
' =' 'distance to the horizon
' =' 'hidden height
' =' 'observer eye height above reference level (e.g. sea level)
' =' 'distance to target along surface or line of sight
' =' 'R / (1k) = refracted radius of the earth
' =' '6371 km = radius of the earth
' =' 'refraction coefficient

Finding the curvature of the Earth

⇒ Flat-Earth: Finding the curvature of the Earth

With the help of a simulation, I show, up to what altitudes the earth appears flat, although it actually has a spherical shape. Using some animations, you can learn how to recognize the curvature of the earth, or in what circumstances it appears flat. The simulation can also simulate refraction. I prove by means of photos, how the simulation depicts reality, by superimposing the simulation results onto photos.

 

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