File:Polar Mesospheric Clouds, Southern Hemisphere 2010-01-30 lrg.jpg
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Summary
[edit]DescriptionPolar Mesospheric Clouds, Southern Hemisphere 2010-01-30 lrg.jpg |
English: This striking astronaut photograph shows polar mesospheric clouds over the Southern Hemisphere on January 30, 2010. These clouds occur over the high latitudes of both the Northern and Southern Hemispheres during their respective summer months at very high altitudes (approximately 76 to 85 kilometers, or 47 to 53 miles). They are most visible during twilight, when the clouds are still illuminated by the setting Sun, while the ground is already dark.
Polar mesospheric clouds are also known as noctilucent or “night-shining” clouds—a property that is clearly visible in this astronaut photograph. The clouds exhibit thin, wispy light blue forms that contrast with the darkness of space (image upper right). Lower levels of the clouds are more strongly illuminated by the Sun and appear light orange to white. Clouds closest to the Earth’s surface are reddish-orange (image center). The image was taken approximately 38 minutes after midnight Greenwich Mean Time (GMT), while the International Space Station was located over the southern Atlantic Ocean. At this time of year, the Sun never sets over Antarctica, but rather traces an arc across the local horizon, allowing polar mesospheric clouds to be observed near local midnight. The International Space Station (ISS) orbit ranges from 52 degrees north to 52 degrees south; combined with the highly oblique (“from-the-side”) views through the Earth’s atmosphere that are possible with hand-held cameras, the ISS is an ideal platform for documenting transient, high-altitude phenomena like polar mesospheric clouds. Another NASA mission, the Aeronomy of Ice in the Mesosphere is dedicated to the study of polar mesospheric clouds, and the satellite is providing daily information about their formation, distribution, and variability. |
Date | |
Source | http://earthobservatory.nasa.gov/IOTD/view.php?id=42774 |
Author | NASA, The image was taken by the Expedition 22 crew |
Licensing
[edit]Public domainPublic domainfalsefalse |
This file is in the public domain in the United States because it was solely created by NASA. NASA copyright policy states that "NASA material is not protected by copyright unless noted". (See Template:PD-USGov, NASA copyright policy page or JPL Image Use Policy.) | ||
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Date/Time | Thumbnail | Dimensions | User | Comment | |
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current | 15:49, 23 February 2010 | 1,440 × 960 (141 KB) | Captain-tucker (talk | contribs) | {{Information |Description={{en|This striking astronaut photograph shows polar mesospheric clouds over the Southern Hemisphere on January 30, 2010. These clouds occur over the high latitudes of both the Northern and Southern Hemispheres during their res |
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Metadata
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Camera manufacturer | NIKON CORPORATION |
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Camera model | NIKON D2Xs |
Exposure time | 1/30 sec (0.033333333333333) |
F-number | f/2.8 |
ISO speed rating | 200 |
Date and time of data generation | 00:38, 30 January 2010 |
Lens focal length | 70 mm |
Orientation | Normal |
Horizontal resolution | 240 dpi |
Vertical resolution | 240 dpi |
Software used | Adobe Photoshop CS4 Macintosh |
File change date and time | 17:00, 19 February 2010 |
Exposure Program | Aperture priority |
Exif version | 2.21 |
Date and time of digitizing | 00:38, 30 January 2010 |
APEX shutter speed | 4.906891 |
APEX aperture | 2.970854 |
APEX exposure bias | 0 |
Maximum land aperture | 3 APEX (f/2.83) |
Metering mode | Pattern |
Light source | Unknown |
Flash | Flash did not fire |
DateTime subseconds | 05 |
DateTimeOriginal subseconds | 05 |
DateTimeDigitized subseconds | 05 |
Color space | sRGB |
Sensing method | One-chip color area sensor |
Custom image processing | Normal process |
Exposure mode | Auto exposure |
White balance | Auto white balance |
Digital zoom ratio | 1 |
Focal length in 35 mm film | 105 mm |
Scene capture type | Standard |
Contrast | Soft |
Saturation | Normal |
Sharpness | Normal |
Subject distance range | Unknown |