Wednesday, October 12, 2011

Mimantean Crater Herschel Displays Subtle Colors in Close Flyby View


Summary: Mimantean crater Herschel displays subtle colors in a close flyby view obtained Feb. 13, 2010, by Cassini Orbiter’s narrow angle camera.


Herschel Crater dominates the right lower half of false color view of northern part of Mimantean moon’s leading hemisphere; mosaic combines ultraviolet, green and infrared filter images with black-and-white, high resolution clear-filter image obtained Feb. 13, 2010, by Cassini orbiter during closest-ever flyby; NASA ID PIA12572; image addition date 2010-03-29; image credit NASA/JPL/Space Science Institute (SSI): May be used for any purpose without prior permission, via NASA JPL Photojournal

Mimantean crater Herschel displays subtle colors in a close flyby view obtained during the Cassini-Huygens spacecraft’s closest-ever flyby Feb. 13, 2010.
An image described by Rebecca Whatmore for the National Aeronautics and Space Administration (NASA) website’s March 29, 2010, multimedia feature, “Color Near Herschel Crater,” reveals subtle colors in the terrain in and around Herschel Crater on Saturnian moon Mimas. The image captures the northern part of the natural satellite’s leading, or forward-facing, hemisphere, which leads in the direction of Mimas’ orbit around its primary.
“The natural color of Mimas visible to the human eye may be a uniform gray or yellow color, but this mosaic has been contrast-enhanced and shows differences at other wavelengths of light,” stated Whatmore. Subtle blues color Herschel Crater and its environs. The older, densely cratered terrain beyond Herschel Crater’s environs exhibits a greenish cast.
“The origin of the color differences is not yet understood, but may be caused by subtle differences in the surface composition between the two terrains,” Whatmore noted. Color variations between the terrain in Herschel Crater’s vicinity and distant terrain also are consistent with false color images obtained Aug. 2, 2005, by Cassini orbiter’s narrow-angle camera.
The Cassini-Huygens spacecraft launched Wednesday, Oct. 15, 1997, at 08:43:00 Universal Coordinated Time (4:43 a.m. Eastern Daylight Time), from Cape Canaveral Air Force Station (CCAFS) Space Launch Complex 40 (SLC-40) as the fourth space probe visitor to Saturn and the first Saturn orbiter. The Cassini-Huygens spacecraft comprises two elements. The Cassini orbiter carries 12 instruments. The Huygens probe is equipped with six instruments.
The spacecraft successfully executed Saturn orbital insertion (SOI) Thursday, July 1, 2004, at 02:48 UTC (Wednesday, June 30, at 10:48 p.m. EDT). On Saturday, Feb. 13, 2010, the spacecraft made its closest-ever flyby of Mimas, approaching within approximately 9,500 kilometers (5,900 miles) of the Saturnian moon.
During the Feb. 13 close flyby, the Cassini orbiter’s narrow-angle camera obtained ultraviolet, green and infrared images of Herschel Crater and its environs. The images were captured at an approximate distance of 16,000 kilometers (10,000 miles) from Mimas.
Based at the Space Science Institute in Boulder, Colorado, the Cassini imaging team reprojected the images, using orthographic projection, into a single mosaic in order to exaggerate the terrain’s color variations. The color image was then combined with a high-resolution, black-and-white image, taken in visible light with Cassini orbiter’s wide-angle camera. The resulting false-color view of Herschel Crater benefits from the high-resolution information provided by the visible light’s clear-filter images and the color information revealed by the ultraviolet, green and infrared filter images.
The Cassini-Huygens mission, commonly known as Cassini, is designed as a collaborative project involving NASA, the European Space Agency (ESA; Agence spatiale europĂ©enne) and the Italian Space Agency (ASI; Agenzia Spaziale Italiana). NASA’s Jet Propulsion Laboratory (JPL) in California designed, developed and assembled the Cassini orbiter and its two onboard cameras, a narrow-angle camera (NAC) and a wide-angle camera (WAC). The Jet Propulsion Laboratory manages the Saturn-focused mission on behalf of NASA’s Science Mission Directorate (SMD) in Washington.
The Cassini orbiter’s name honors Italian (naturalized French astronomer and engineer Giovanni Domenico Cassini (June 8, 1625-Sept. 14, 1712). Cassini’s astronomical contributions include discovering four Saturnian moons and Saturn’s Cassini Division. Cassini discovered his first Saturnian moon, Iapetus in Oct. 25, 1671. He discovered Rhea on Dec. 23, 1672. His discovery of Tethys occurred on March 21, 1684. Cassini made his discovery of Dione on March 21, 1684. He discovered the Cassini Division, a region between Saturn’s A ring and B ring, in 1675 via a refracting telescope at the Paris Observatory.
The Huygens probe honors Christiaan Huygens (April 14, 1629-July 8, 1695). The Dutch astronomer, inventor, mathematician and physicist’s astronomical contributions include discovery of Titan, Saturn’s largest moon, and studying Saturn’s rings. Huygens made his discovery of Saturn’s Titanic moon on March 25, 1655.
The takeaways for Mimantean crater Herschel’s subtle color displays are that the Cassini-Huygens spacecraft’s Cassini orbiter obtained ultraviolet, green and infrared filtered images of the crater’s neighborhood during a closest-ever flyby on Feb. 13, 2010; that a false color view released by NASA on March 29 shows bluish colors for Herschel Crater and its environs; that terrain distanced from the large impact crater reveals a greenish cast; and that the terrain-dependent color variations are hypothesized as reflecting “subtle differences in the surface composition between the two terrains.”

Artist’s concept of Saturn Orbital Insertion (SOI) maneuver shows that the Cassini-Huygens spacecraft has just crossed the ring plane, just after the beginning of firing by the spacecraft’s main engine (center) in order to reduce velocity with respect to Saturn; NASA ID PIA03883; image addition date 2002-12-11; image credit NASA/JPL: May be used for any purpose without prior permission, via NASA JPL Photojournal

Acknowledgment
My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:
Herschel Crater dominates the right lower half of false color view of northern part of Mimantean moon’s leading hemisphere; mosaic combines ultraviolet, green and infrared filter images with black-and-white, high resolution clear-filter image obtained Feb. 13, 2010, by Cassini orbiter during closest-ever flyby; NASA ID PIA12572; image addition date 2010-03-29; image credit NASA/JPL/Space Science Institute (SSI): May be used for any purpose without prior permission, via NASA JPL Photojournal @ https://photojournal.jpl.nasa.gov/catalog/PIA12572; Generally not subject to copyright in the United States; may use this material for educational or informational purposes, including photo collections, textbooks, public exhibits, computer graphical simulations and Internet Web pages; general permission extends to personal Web pages, via NASA Image and Video Library https://images.nasa.gov/details/PIA12572; via NASA Cassini-Huygens mission pages @ https://www.nasa.gov/mission_pages/cassini/multimedia/pia12572.html
Artist’s concept of Saturn Orbital Insertion (SOI) maneuver shows that the Cassini-Huygens spacecraft has just crossed the ring plane, just after the beginning of firing by the spacecraft’s main engine (center) in order to reduce velocity with respect to Saturn; NASA ID PIA03883; image addition date 2002-12-11; image credit NASA/JPL: May be used for any purpose without prior permission, via NASA JPL Photojournal @ https://photojournal.jpl.nasa.gov/catalog/PIA03883; Generally not subject to copyright in the United States; may use this material for educational or informational purposes, including photo collections, textbooks, public exhibits, computer graphical simulations and Internet Web pages; general permission extends to personal Web pages, via NASA Image and Video Library @ https://images.nasa.gov/details-PIA03883

For further information:
Herschel, William. “Account of the Discovery of a Sixth and Seventh Satellite of the Planet Saturn; With Remarks on the Construction of Its Ring, Its Atmosphere, Its Rotation on an Axis, and Its Spheroidical Figure. Read November 12, 1789.” Philosophical Transactions of the Royal Society of London, vol. LXXX, for the Year 1790, Part I: 1-20. London UK: Lockyer Davis and Peter Elmsly, Printers to The Royal Society, MDCCXC (1790).
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/51828893
Herschel, William. “Description of a Forty-Feet Reflecting Telescope. Read June 11, 1795.” Philosophical Transactions of the Royal Society of London for the Year MDCCXCV, vol. LXXXV, Part II: 347-409. London UK: Peter Elmsly, Printer to The Royal Society, 1795.
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/51831451
International Astronomical Union. “Herschel .” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature. Last updated Aug. 14, 2008.
Available @ https://planetarynames.wr.usgs.gov/Feature/2478
Lavoie, Sue, site manager. “PIA03883: Artists’s Conception of Cassini Saturn Orbit Insertion.” NASA Jet Propulsion Laboratory Photojournal. Image addition date Dec. 11, 2002.
Available @ https://photojournal.jpl.nasa.gov/catalog/pia03883
Levy, David H. Skywatching. Revised and updated. San Francisco CA: Fog City Press, 1994.
Marriner, Derdriu. “Mimantean Crater Herschel Honors Mimas Discoverer William Herschel.” Earth and Space News. Wednesday, Sept. 7, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/09/mimantean-crater-herschel-honors-mimas.html
Marriner, Derdriu. “Mimantean Crater Herschel Partially Overlies Oeta Chasma.” Earth and Space News. Wednesday, Oct. 5, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/09/mimantean-crater-herschel-partially.html
Marriner, Derdriu. “William Herschel Discovered Mimas With Newly Built 40-Foot Telescope.” Earth and Space News. Wednesday, Sep. 21, 2019.
Available @ https://earth-and-space-news.blogspot.com/2011/09/william-herschel-discovered-mimas-with.html
Marriner, Derdriu. “William Herschel Discovered Saturnian Moon Mimas Sept. 17, 1789.” Earth and Space News. Wednesday, Sept. 14, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/09/william-herschel-discovered-saturnian.html
Moore, Patrick, Sir. Philip’s Atlas of the Universe. Revised edition. London UK: Philip’s, 2005.
U.S. Geological Survey. “Preliminary Pictorial Map of Mimas.” Atlas of the Saturnian Satellites. IMAP 1482. Prepared for the Voyager Imaging Team in cooperation with the Jet Propulsion Laboratory, California Institute of Technology and the National Aeronautics and Space Administration. Directed by R.M. (Raymond Milner) Batson / U.S. Geological Survey Branch of Astrogeologic Studies. Airbrush representation by Jay L. Inge. Data preparation and preliminary image processing by K.F. Mullins, Christopher Isbell, E.M. Lee, H.G. Morgan and B.A. Skiff. Reston VA: U.S. Geological Survey, 1982.
Available @ https://pubs.er.usgs.gov/publication/i1489
Available @ http://171.67.35.48/view/6829740
Whatmore, Rebecca, ed. “Color Near Herschel Crater.” NASA > Mission Pages > Cassini-Huygens Mission to Saturn > Multimedia. March 29, 2010. Page last updated May 12, 2010.
Available @ https://www.nasa.gov/mission_pages/cassini/multimedia/pia12572.html
Whatmore, Rebecca, ed. “Streaked Craters in False-Color.” NASA > Mission Pages > Cassini-Huygens Mission to Saturn > Multimedia. March 29, 2010. Available @ https://www.nasa.gov/mission_pages/cassini/multimedia/pia12571.html
Whatmore, Rebecca, ed. “Streaks and Markings on Mimas.” NASA > Mission Pages > Cassini-Huygens Mission to Saturn > Multimedia. March 29, 2010.
Available @ https://www.nasa.gov/mission_pages/cassini/multimedia/pia12571.html



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