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Lunar Reconnaissance Orbiter Camera (LROC)

(glossary entry)


The LROC is a set of three cameras photographing the Moon at close range from NASA's LRO spacecraft.

Additional Information

  • The LROC consists of one wide (100 m/pixel nominal resolution, WAC or Wide Angle Camera) and two narrow (0.5 m/pixel nominal resolution, NAC or Narrow Angle Camera) field of view cameras. They were designed and built by Malin Space Science Systems. The NAC images are taken with a telescope similar to the ones used by many amateurs (198 mm, or about 8 inches, aperture). The WAC views are produced with a tiny camera having an aperture of just 1.2 mm. A set of filters bonded to the WAC sensor makes it possible to photograph the Moon nearly simultaneously at seven discrete wavelengths.
  • Images of special interest are mentioned (with commentary) on the Featured Image news page and collected in the Browse Gallery. Most are also listed in this Wiki's LROC - Browse Gallery Resource.
  • The whole set of released LROC data is accessible through an interactive Image Map, through a text-based Image Search (specifying Product ID, or the desired coordinates, lighting and other parameters) or by browsing the vast collection of Thumbnail Images .
    • To retrieve images with the Image Map one must first zoom in on the area of interest, then use the "Toggle Layers" control (in the upper left) to select some combination of NAC or WAC images (which will superimpose the footprints of available frames on the underlying map), and finally click the exact point of interest with the "Click to change mouse-action..." option set to "Get Footprint Info". Thumbnails of all images in the selected categories that include that point will then appear at the bottom of the screen. Clicking on the thumbnail links to a page displaying a zoomable version of the image, selected support information and links to the primary data. The latter comes in two forms: EDR or Engineering Data Records are the original 8-bit data transmitted by the camera, CDR or Calibrated Data Records have been photometrically calibrated and corrected (presumably to a linear intensity range). Most images are also available in an 8-bit (256 gray level) "PTIF" format, which is apparently the "pyramid" of calibrated images used to generate the Zoomable display.
    • The Image Search and Thumbnail pages lead to the same image display pages.
    • At present it appears that the display pages for most LROC products of known Product ID can be found directly with a (case sensitive) link of the form:
  • The second to last letter in the Product ID has the following significance:
    • R : right NAC image
    • L : left NAC image
    • M : monochrome WAC image
    • U : ultraviolet bands (2) only WAC image
    • V : visible bands (5) only WAC image
    • C : all 7 bands WAC image
  • Images from the LROC experiment are also available in the PDS Planetary Image Atlas.
  • The LROC WAC data are presented as a time series of framelets (14x1024 pixel images in the monochrome mode; groups of even smaller panels in the multi-spectral modes), exposed as LRO flys over the Moon. The individual framelets are frequently inverted relative to the direction of travel, causing the content to be hard to perceive in the raw format. For Windows PC's there is utility program available, inspired by the work of John Moore and Rick Evans, which can be used to quickly invert (if necessary) and stack the framelets representing a single waveband into a more intelligible mosaic. John Moore has prepared detailed instructions for using that utility for Assembling WAC Images.
  • On 18 March 2011 a new browse-for-an-image interface, called ‘Quickmap’, was launched by the LROC Team of scientists. The interface presents a global lunar map in the equidistant, cylindrical format (the poles are in the orthographic format), and various options, like, navigation, searching, zooming...etc., can be changed. The main feature with Quickmap is that it allows a user to initially view an area from a reduced WAC resolution; and then access the high NAC resolution views (in red rectangles) – available as a list when using the Search for option. As of writing, 20 March 2011, the interface has not yet been fully refined, however, this is expected to change over the coming weeks and months. - JohnMoore2 Mar 20, 2011

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