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”
During a total solar eclipse, the Moon’s side facing Earth does not receive sunlight but still receives light reflected from Earth’s surface. The phenomenon is called Earthshine and can be captured using a camera with a long exposure.
Flat-Earthers demand visual evidence of the Moon blocking the Sun during a solar eclipse. Earthshine provides this visual evidence & shows that the Moon is blocking the Sun.
Continue reading “Earthshine Shows the Moon Obscuring the Sun During a Total Solar Eclipse”
A satellite’s size is as small as a mobile phone to as large as a football field. The largest is 109 m, still far too small compared to Earth at 2742 km in diameter.
Satellites are not visible in Earth images. Flat-Earthers use the fact as “evidence” of deception. In reality, satellites are tiny compared to Earth. They are invisible in Earth images the same way ants are not visible in images of a football field.
Continue reading “Satellites in Earth’s Photos”
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”
A camera with a zoom lens has a variable field of view but a fixed output resolution. As a result, its angular resolution depends on the zoom factor. Changing the zoom factor will change the ability of the camera to resolve a distant object.
Flat-Earthers show us zooming in reveals an unseen object & uses it to “disprove” Earth’s curve. In reality, the object was previously unseen due to the angular resolution limit at wide zoom. It is not far enough to be obscured by Earth’s curvature.
Continue reading “Zoom, Digital Resolution, and the Visibility of a Distant Object”
To monitor the ozone hole, NOAA launches a balloon every week on several locations on Earth. Scientists who launch the balloons like to create multiple exposure photos of the event. A single balloon appears multiple times in the resulting photos.
Flat-Earthers saw the “many balloons in a row” photos, & they incorrectly use them as the “explanation” of the appearance of the SpaceX Starlink satellites. In reality, the photos are just multiple exposure photos. There is only a single balloon, but taken multiple times and then merged into a single photo.
Continue reading “Multiple Exposure Photos of Balloons and SpaceX StarLink Satellites”
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.
Continue reading “Ultra Wide-Angle Lens”
Camera zoom works by enlarging the center portion of the image, or in other words, by making its field-of-view narrower. Zooming in on the setting sun will not reveal more of the sun and will only enlarge the size of the sun in the resulting image.
Flat-Earthers claim that zooming in on a setting sun will reveal the full sun and somehow lift it out of the water. In reality, they used incorrect exposure settings, making the sun still above the horizon appear already half-obscured by Earth’s curvature.
Zooming on the setting sun will never reveal the sun already obstructed by Earth’s curvature.
Continue reading “Zooming-In on the Setting Sun”
In photography, bokeh is the way a lens renders out-of-focus points of light. The shape of bokeh depends on the shape of the lens’s aperture more than the out-of-focus objects themselves.
Flat-Earthers fail to take properly-focused photos of stars and planets because of their lack of photography skills and because their cameras are not suitable for the purpose. They are just getting bokeh, which tells us more about their equipment (and lack of knowledge) than the actual intended objects.
Continue reading “Bokeh”
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”
Image noise is a random variation of brightness or color information produced by a photo film or digital sensor. Image noise is an undesirable by-product of photography and does not come from the actual objects in the picture.
Image noise can be in the salt-and-pepper type, forming bright dots in the dark parts of the image. When appearing in the dark part of the Moon, flat-Earthers incorrectly claim they are stars, “proving” that the Moon is transparent. In reality, these are just image noise, not part of the actual objects.
Continue reading “Image Noise and The “Transparent Moon” Misinformation”
By utilizing perspective compression, it will be easier for us to observe the curvature of an object if the object is curved.
Flat-Earthers like to deliberately choose a vantage point where it is difficult to see Earth’s curvature, and they use it to “prove” the curvature does not exist. In reality, they only make it more difficult to see the curvature. It does not mean the curve is not there.
Continue reading “Perspective Compression: Determining If a Curvature Exists”
At the cruising altitude of a jet airliner, Earth’s curvature is too slight for us to notice casually. But with planning and careful observation, it is not impossible to see the curvature. Continue reading “Observing Earth’s Curvature From a Flight”
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”
Flat-Earthers and other conspiracy theorists incorrectly claim that the shadows in photos taken on the Moon in the Apollo missions are inconsistent. In reality, it is just due to their confirmation biases, and we can easily explain how the shadows were formed.
The perspective effect can cause parallel shadows to appear angled to each other and converge to a distant point. Conspiracy theorists incorrectly claim that non-parallel shadows can only be caused by a nearby light source.
Continue reading “Shadows in Photographs Taken on the Moon”
It is impossible to positively prove the authenticity of a photo beyond any doubt unless we take the photos ourselves. Instead, we gather as much information as possible related to the photo, evaluate the information, then use inductive reasoning to determine if the photo is real. And the conclusion will always be a probability, not a certainty.
Flat-Earthers like to demand us to prove that a particular photo is real, and if we cannot, they will conclude the photo is fake. In reality, while we might be able to prove a photo is not real, at the very best, we can only say there is no reason to believe the photo is not real from all the available information. This applies to practically all photos and also plenty of other things in everyday life.
Continue reading “Determining the Authenticity of a Photo”
The sunlit part of the moon is far brighter than the stars in the background. But cameras have dynamic range limitations. They cannot capture extremely bright and extremely dim objects at the same time. We can increase the exposure to reveal the stars, but then the moon will appear washed out, with no visible details.
Flat-Earthers use the lack of stars in photos taken from space to dismiss them as fake. In reality, the reason for the lack of stars is the same reason stars are also missing in photos of the Moon taken with the correct exposure.
Continue reading “Camera Exposure Settings to Capture the Moon and Stars”
Visual albedo is the measure of the reflection of sunlight out of the total solar radiation received by an astronomical body, taking into account only the visible light. The visual albedo of the Earth is 0.37, and the Moon’s is 0.12.
The Moon appears dark if the Earth also appears in the same photograph. Flat Earthers use the fact to dismiss such photos as fake. In reality, the Moon’s brightness in a photo is just a matter of choosing the correct camera exposure. But if Earth is also present, increasing the exposure will make the Earth appear too bright.
Continue reading “Visual Albedo of the Moon and the Earth”
Glare can appear around light sources, causing them to appear larger in a photo. The higher the exposure value of the camera, the larger the glare will appear on the resulting photo.
Much flat-Earth misinformation arises from misunderstandings about photography, such as about glare and how to eliminate glare by changing the exposure or by using a solar filter. Using the exposure setting for everyday scenes to capture a photograph of the sun will give us a glare around the Sun. To take a photo of the actual size of the Sun, we need to reduce the exposure, either by changing the in-camera exposure settings or by using a solar filter.
Continue reading “Glare”