Wednesday, November 19, 2014
Planet Earth in 4K
Published on Nov 15, 2014 James Tyrwhitt-Drake
"A timelapse of Earth in 4K resolution, as imaged by the geostationary Elektro-L weather satellite, from May 15th to May 19th, 2011. Elektro-L is located ~40,000 km above the Indian ocean, and it orbits at a speed that causes it to remain over the same spot as the Earth rotates. The satellite creates a 121 megapixel image (11136x11136 pixels) every 30 minutes with visible and infrared light wavelengths. The images were edited to adjust levels and change the infrared channel from orange to green to show vegetation more naturally. The images were resized by 50%, misalignments between frames were manually corrected, and image artifacts that occurred when the camera was facing towards the sun were partially corrected. The images were interpolated by a factor of 20 to create a smooth animation. The animation was rendered in the Youtube 4K UHD resolution of 3840x2160. An original animation file with a resolution of (5568x5568) is available on request.
To answer frequently asked questions; why are city lights, the Sun, and other stars not visible? City lights are not visible because they are thousands of times less bright than the reflection of sunlight off the Earth. If the camera was sensitive enough to detect city lights, the Earth would be overexposed. The Sun is not visible due to mechanisms used to protect the camera CCD from direct exposure to sunlight. A circular mask on the CCD ensures that only the Earth is visible. This mask can be seen as pixelation on Earth's horizon. The mask also excludes stars from view, although they would not be bright enough to be visible to this camera.
Image Credit: NTs OMZ (http://eng.ntsomz.ru/electro).
Image processing by James Tyrwhitt-Drake"