NASA maintains a database of astronaut photography in eol.jsc.nasa.gov that we can search by many parameters, including focal length. By searching for focal length above 28mm, we can ensure the resulting images are not fisheye.
Flat-Earthers claim all NASA images are fisheye. In reality, most images in eol.jsc.nasa.gov are not fisheye. NASA also preserves the images’ EXIF data containing the camera & lens info. Sometimes even the raw images are available.
Continue reading “NASA’s Non-Fisheye Images”
A photographic lens may have a specific distortion characteristic and strength that may differ from another lens. However, despite the differences, a straight line will always appear straight if it crosses the center of the frame.
Flat-Earthers like to dismiss images taken by a fisheye lens. In reality, the attributes of such a lens are well known. We can use the knowledge to determine if a line in the image is straight, even if it was taken using a fisheye lens.
Continue reading “Fisheye Lenses and Lens Distortions”
An ultra wide-angle lens produces images with an extremely wide angle of view. A lens with a focal length shorter than 24 mm (full-frame equivalent) is considered an ultra wide-angle lens. Ultra wide-angle lenses come in two varieties: rectilinear lens and curvilinear, or fisheye lens.
Because of their wide field of view, Earth’s curvature is easier to observe using an ultra-wide lens. Flat-Earthers incorrectly assumed it means a fisheye lens that distorts straight lines. In reality, there are rectilinear ultra wide-angle lenses that preserve straight lines. With these lenses, if the horizon looks curved, then it must be due to Earth’s curvature itself.
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Defishing is a process for removing barrel distortions from fisheye images, producing rectilinear images that preserve straight lines. A different fisheye lens produces a different amount of distortion & needs a different defishing strength.
Flat-Earthers like to apply a stronger defishing parameter than necessary with the goal not to remove the distortions but to make the horizon flat. As a result, they not only remove barrel distortion from the image but also introduce pincushion distortion that straightens the curved horizon.
The horizon in the end image might appear flat. However, it is due to the distortion these flat-Earthers deliberately introduced to the image, not because the horizon is flat.
Continue reading “Defishing Fisheye Images Excessively to Flatten the Curved Horizon”
The magnitude of the curvature that appears in a photograph of Earth’s curvature depends on several factors:
- The observer’s altitude.
- The camera’s field of view or focal length.
- The distortion characteristics of the camera lens.
Flat-Earthers like to dismiss a photo of Earth’s curvature by comparing it to another photo showing a different amount of curvature. In reality, to compare the visible curvature, we need to ensure all the images were taken from the same altitude, same field of view, and account for the lens’ distortion.
Continue reading “Magnitude of Visible Earth’s Curvature in a Photograph”
If Earth is a sphere, how is it possible for flat-Earthers to show us “images of flat Earth” taken from high-altitude balloons? These are the modus operandi of unscrupulous flat-Earthers to obtain such images in an attempt to deceive us.
Continue reading “Modus Operandi of Flat-Earthers to Obtain “Images of Flat Earth” to Deceive Us”
Cameras with a fisheye lens are used in the ISS, high-altitude balloons, rocket bodies, and other purposes. The reason is that fisheye lenses have several advantages over rectilinear lenses.
Flat-Earthers claim there is an evil intention behind the usage of fisheye lenses. In reality, the use of fisheye lenses is not unreasonable. If it is desired to have a rectilinear image output, then it is not hard to defish fisheye images to rectilinear ones..
Continue reading “Why Fisheye Lenses Are Used”
Red Bull Stratos was a high-altitude diving project involving Felix Baumgartner. In 2012, Felix Baumgartner flew 39 km (24 mi) into the stratosphere in a helium balloon before free falling in a pressure suit and then parachuting to Earth. Flat-Earthers invented various excuses to dismiss the resulting footage from the project.
Continue reading “Felix Baumgartner and Red Bull Stratos”
In images taken using a fisheye lens, a straight line will remain straight if it crosses the center of the image. We can use this attribute to determine if a line is straight in reality.
In any fisheye videos taken from a high altitude, there should be plenty of moments where the horizon crosses the center of the image, and we can use those to determine that the horizon line is curved in the real world.
Continue reading “Fisheye Videos”
The United Arab Emirates astronaut, Hazza Al Mansouri, took pictures of Earth’s features like the Nile and the Persian Gulf during his visit to the ISS. Flat-Earthers claim the pictures are fake because the various objects appear very large compared to the size of the Earth in the picture. The reason is that they do not understand that the ISS is only about 400 km above Earth’s surface, and only a very small amount of the Earth’s surface is visible from the ISS
Continue reading “Pictures of Earth’s Surface from the UAE Astronaut Hazza Al-Mansouri”
In 2017, the group who name themselves ‘ASAN’ staged a protest to Donald Trump by sending a high-altitude balloon carrying a camera and a crude message, which was quoted from a statement by Edgar Mitchell, an astronaut from the Apollo 14 mission.
Some unscrupulous flat-Earthers hijacked the protest and turned it as if ASAN did it to prove Earth’s curvature and to insult them. These flat-Earthers pointed out that ASAN somehow “forgot” to conceal the fact that a fisheye lens was used. In reality, it is never the intention of ASAN to prove Earth’s curvature, nor to throw insults to flat-Earthers.
Continue reading “The Space Protest by ASAN That Was Hijacked by Flat-Earthers for Provocation”
The amount of curvature that appears in a photograph of a sphere depends on 1. The radius of the sphere, 2. Camera distance from the sphere, 3. Field of view of the camera, and 4. The distortion characteristic of the camera being used.
The ‘curvature fitting game’ has been flat-Earthers’ favorite pastime. They would try to fit a photograph of Earth’s curvature with another. If they find the result is not proportionally correct, they will make fun of it. They are wrong. Two different photos of a sphere can be taken differently and would show a different curve, even if the object being photographed is the same object.
Continue reading “The Curvature Fitting Game”
A fisheye lens distorts images. It results in images having barrel distortions. In a fisheye lens, a straight line can appear curved. But some flat-Earthers don’t realize that the opposite is also true, a fisheye lens can easily make a curved line look straight.
Continue reading “Fisheye Lenses Can Make Curved Lines Appear Flat”
High-altitude balloon footage is often abused by flat-Earthers to show us that the Earth is flat when seen from a high altitude.
We analyzed more than two dozens of footage taken from high-altitude balloons on YouTube, and we can easily conclude the curvature is there and usually easy to spot, including in the cases where flat-Earthers use the video as ‘proof’ of a flat Earth.
Continue reading “Curvature of the Horizon in High-Altitude Balloon Footage”
Little Piggy is the nickname of a helium balloon launched by IndianaCaver. It reached the altitude of almost 37 km before it finally ruptured and fell to the Earth. Before that, it took several hours of video, and IndianaCaver made these video available on YouTube.
Then, some flat-Earthers cherry-picked bits of the video where the horizon looked flat and presented it as ‘proof’ of flat-Earth. These are widely circulated in various memes and forms, even years after the originals were published.
But, can we use these videos as ‘proof’ of flat-Earth?
Continue reading “The Little Piggy Balloon Footage Proves Earth is a Sphere, not Flat”