File:Phobos shadow 1999-09-01.gif

From Infogalactic: the planetary knowledge core
Jump to: navigation, search
Phobos_shadow_1999-09-01.gif ‎(288 × 512 pixels, file size: 164 KB, MIME type: image/gif)

Summary

Credit: NASA/JPL/Malin Space Science Systems <a rel="nofollow" class="external autonumber" href="http://www.jpl.nasa.gov/images/policy/index.cfm">[1]</a>

<a rel="nofollow" class="external autonumber" href="http://www.msss.com/moc_gallery/policy.html">[2]</a>

The <a href="https://en.wikipedia.org/wiki/penumbra" class="extiw" title="en:penumbra">penumbral</a> shadow of <a href="https://en.wikipedia.org/wiki/Phobos_(moon)" class="extiw" title="en:Phobos (moon)">Phobos</a> on <a href="https://en.wikipedia.org/wiki/Mars_(planet)" class="extiw" title="en:Mars (planet)">Mars</a> on <a href="https://en.wikipedia.org/wiki/September_1" class="extiw" title="en:September 1">September 1</a> <a href="https://en.wikipedia.org/wiki/1999" class="extiw" title="en:1999">1999</a>, imaged by <a href="https://en.wikipedia.org/wiki/Mars_Global_Surveyor" class="extiw" title="en:Mars Global Surveyor">Mars Global Surveyor</a>. The center of the shadow was at approximately 14°N 236°W (<a rel="nofollow" class="external text" href="http://pdsmaps.wr.usgs.gov/explorer-bin/mapmars3.cgi?WHEREFROM=PZ&VERSION=ADVANCED&DATA_SET_NAME=v2mars_viking_bw&PIXEL_TYPE=BIT8&SCALE=pixels/degree&PROJECTION=SINUSOIDAL&RESOLUTION=64&RESAMP_METHOD=NEAREST_NEIGHBOR&BANDS_SELECTED=1&FORMAT=JPEG&LONBOX=20&LATBOX=10&GRIDLINE_FREQUENCY=1&STRETCH=AUTO&LAT=13&LON=235&LINE=960&SAMP=960">map</a>) at 20:49:02.4 <a href="https://en.wikipedia.org/wiki/UTC" class="extiw" title="en:UTC">UTC</a> Earth time.

Note that the timestamp "20:13:05" printed on the photo does not correspond to the actual time that the shadow was imaged, rather it represents the "image start time" of a vertically much larger original image that took nearly an hour to acquire. <a rel="nofollow" class="external text" href="http://www.msss.com/moc_gallery/m07_m12/images/M07/M0700166.html">M07-00166</a> (red) and <a rel="nofollow" class="external text" href="http://www.msss.com/moc_gallery/m07_m12/images/M07/M0700167.html">M07-00167</a> (blue).

<a href="https://en.wikipedia.org/wiki/Mars_Global_Surveyor" class="extiw" title="en:Mars Global Surveyor">Mars Global Surveyor</a> orbits <a href="https://en.wikipedia.org/wiki/Mars_(planet)" class="extiw" title="en:Mars (planet)">Mars</a> in a sun-synchronous polar orbit with <a href="https://en.wikipedia.org/wiki/orbital_period" class="extiw" title="en:orbital period">orbital period</a> 117.65 minutes, moving from south pole to north pole, and continuously points its camera straight down. The result is an image in the form of a very long thin vertical strip, where the pixels in the top part of the image are imaged nearly one hour after those in the bottom part of the image. However, "downtrack summing" usually reduces the vertical size of the image by a considerable factor by merging multiple lines into one.

In this case the image start time is 20:13:04.69 <a href="https://en.wikipedia.org/wiki/UTC" class="extiw" title="en:UTC">UTC</a>, the line integration time is 80.48 milliseconds, and the downtrack summing factor is 27. The shadow is about 8 pixels high, centered at 993 pixels from the bottom of the original 1600-pixel-high image. We add (993 * 0.08048 * 27) = 2157.75 seconds = 35 minutes 57.75 seconds to get a time of 20:49:02.4 UTC for the center of the shadow.

External links

Licensing

Lua error in package.lua at line 80: module 'strict' not found.

File history

Click on a date/time to view the file as it appeared at that time.

Date/TimeThumbnailDimensionsUserComment
current01:19, 14 January 2017Thumbnail for version as of 01:19, 14 January 2017288 × 512 (164 KB)127.0.0.1 (talk)Credit: NASA/JPL/Malin Space Science Systems <a rel="nofollow" class="external autonumber" href="http://www.jpl.nasa.gov/images/policy/index.cfm">[1]</a> <p><a rel="nofollow" class="external autonumber" href="http://www.msss.com/moc_gallery/policy.html">[2]</a> </p> <p>The <a href="https://en.wikipedia.org/wiki/penumbra" class="extiw" title="en:penumbra">penumbral</a> shadow of <a href="https://en.wikipedia.org/wiki/Phobos_(moon)" class="extiw" title="en:Phobos (moon)">Phobos</a> on <a href="https://en.wikipedia.org/wiki/Mars_(planet)" class="extiw" title="en:Mars (planet)">Mars</a> on <a href="https://en.wikipedia.org/wiki/September_1" class="extiw" title="en:September 1">September 1</a> <a href="https://en.wikipedia.org/wiki/1999" class="extiw" title="en:1999">1999</a>, imaged by <a href="https://en.wikipedia.org/wiki/Mars_Global_Surveyor" class="extiw" title="en:Mars Global Surveyor">Mars Global Surveyor</a>. The center of the shadow was at approximately 14°N 236°W (<a rel="nofollow" class="external text" href="http://pdsmaps.wr.usgs.gov/explorer-bin/mapmars3.cgi?WHEREFROM=PZ&VERSION=ADVANCED&DATA_SET_NAME=v2mars_viking_bw&PIXEL_TYPE=BIT8&SCALE=pixels/degree&PROJECTION=SINUSOIDAL&RESOLUTION=64&RESAMP_METHOD=NEAREST_NEIGHBOR&BANDS_SELECTED=1&FORMAT=JPEG&LONBOX=20&LATBOX=10&GRIDLINE_FREQUENCY=1&STRETCH=AUTO&LAT=13&LON=235&LINE=960&SAMP=960">map</a>) at 20:49:02.4 <a href="https://en.wikipedia.org/wiki/UTC" class="extiw" title="en:UTC">UTC</a> Earth time. </p> <p>Note that the timestamp "20:13:05" printed on the photo does <i>not</i> correspond to the actual time that the shadow was imaged, rather it represents the "image start time" of a vertically much larger original image that took nearly an hour to acquire. <a rel="nofollow" class="external text" href="http://www.msss.com/moc_gallery/m07_m12/images/M07/M0700166.html">M07-00166</a> (red) and <a rel="nofollow" class="external text" href="http://www.msss.com/moc_gallery/m07_m12/images/M07/M0700167.html">M07-00167</a> (blue). </p> <p><a href="https://en.wikipedia.org/wiki/Mars_Global_Surveyor" class="extiw" title="en:Mars Global Surveyor">Mars Global Surveyor</a> orbits <a href="https://en.wikipedia.org/wiki/Mars_(planet)" class="extiw" title="en:Mars (planet)">Mars</a> in a sun-synchronous polar orbit with <a href="https://en.wikipedia.org/wiki/orbital_period" class="extiw" title="en:orbital period">orbital period</a> 117.65 minutes, moving from south pole to north pole, and continuously points its camera straight down. The result is an image in the form of a very long thin vertical strip, where the pixels in the top part of the image are imaged nearly one hour after those in the bottom part of the image. However, "downtrack summing" usually reduces the vertical size of the image by a considerable factor by merging multiple lines into one. </p> <p>In this case the image start time is 20:13:04.69 <a href="https://en.wikipedia.org/wiki/UTC" class="extiw" title="en:UTC">UTC</a>, the line integration time is 80.48 milliseconds, and the downtrack summing factor is 27. The shadow is about 8 pixels high, centered at 993 pixels from the bottom of the original 1600-pixel-high image. We add (993 * 0.08048 * 27) = 2157.75 seconds = 35 minutes 57.75 seconds to get a time of 20:49:02.4 UTC for the center of the shadow. </p> <h2><span class="mw-headline" id="External_links">External links</span></h2> <ul> <li> <a rel="nofollow" class="external text" href="http://mars.jpl.nasa.gov/mgs/msss/camera/images/11_1_99_phobos/index.html">NASA press release</a> (<a href="https://en.wikipedia.org/wiki/November_1" class="extiw" title="en:November 1">November 1</a> <a href="https://en.wikipedia.org/wiki/1999" class="extiw" title="en:1999">1999</a>)</li> <li> <a rel="nofollow" class="external text" href="http://www.msss.com/moc_gallery/m07_m12/gmtables/M07-gm.1999-09-01.html">MOC Global-Map Images, Subphase M07</a> </li> <li> <a rel="nofollow" class="external text" href="http://www.msss.com/moc_gallery/">Mars Global Surveyor Mars Orbiter Camera Image Gallery</a> </li> </ul>
  • You cannot overwrite this file.

The following page links to this file:

Retrieved from "https://infogalactic.com/w/index.php?title=File:Phobos_shadow_1999-09-01.gif&oldid=724178616"