2015 Publication Year 2020-05-05T14:39:34Z Acceptance in OA@INAF Albedo Feature Title Kardevan, Péter; HARGITAI, HENRIK; ZINZI

Total Page:16

File Type:pdf, Size:1020Kb

2015 Publication Year 2020-05-05T14:39:34Z Acceptance in OA@INAF Albedo Feature Title Kardevan, Péter; HARGITAI, HENRIK; ZINZI Publication Year 2015 Acceptance in OA@INAF 2020-05-05T14:39:34Z Title Albedo Feature Authors Kardevan, Péter; HARGITAI, HENRIK; ZINZI, ANGELO; ESPOSITO, Francesca DOI https://doi.org/10.1007/978-1-4614-3134-3_461 Handle http://hdl.handle.net/20.500.12386/24519 Comp. by: Udayasankar Stage: Revises1 Chapter No.: Title Name: EPL_214584 Date:27/2/15 Time:05:23:59 Page Number: 30 A 30 Albedo Feature Ruff SW, Christensen PR (2002) Bright and dark regions surroundings. Albedo features were traditionally on Mars: particle size and mineralogical characteris- identified by doing spectrally integrated observa- tics based on thermal emission spectrometer data. J Geophys Res 107(E12):5127. doi:10.1029/ tion of the reflected sunlight with a telescope in 2001JE001580 the visible spectrum range of light and having Schenk P, Hamilton DP, Johnson RE, McKinnon WB, adequate spatial resolution to resolve distinct Paranicas C, Schmist J, Showalter MR (2011) Plasma, parts of the surface of the object. Detection of plumes and rings: Saturn system dynamics as recorded in global color patterns on its midsize icy satellites. the brightness variations is today extended to Icarus 211:740–757 photometric (radiometric) measurements with See TJJ (1910) On the craters, mountains, Maria and other modern satellite/spacecraft spectrophotometers phenomena observed on the surface of the Moon, and or spectroradiometers at separate monochromatic on the indicated processes of planetary growth. In: Researches on the evolution of the stellar systems. II: wavelengths or integrated observations in other the capture theory of cosmical evolution. Thos. wavelength regions as well (see spectral albedo, P. Nichols, Lynn, Mas https://archive.org/details/ narrowband albedo, and broadband albedo). researchesonevol02seetuoft Albedo features result from those brightness var- Soter S (1974) IAU colloquium 28, Cornell University. Cited by Tamayo et al. (2011) iations, that are due to variations of the reflective Spencer JR, Calvin WM, Person MJ (1995) Charge- properties (often referred to as albedo) of coupled-device spectra of the Galilean satellites: a planetary surface. molecular oxygen on Ganymede. J Geophys Res 100:19049–19056 Tamayo D, Burns JA, Hamilton DP, Hedman MM Variants (2011) Finding the trigger to Iapetus’ odd global Albedo pattern, albedo marking. albedo pattern: dynamics of dust from Saturn’s irreg- ular satellites. Icarus 215:260–278 IAU Definition Geographic area distinguished by amount of reflected light (IAU Gazetteer 2014). Albedo Feature Identification Pe´ter Kardeván1, Henrik Hargitai2, 3 4 Angelo Zinzi and Francesca Esposito The identification and mapping of albedo features 1 retired from Department of Environmental are achieved through observations of the relative Geology, Geological and Geophysical Institute of brightness variations of the planetary surfaces Hungary, Budapest, Hungary that can be carried out either by photographic 2 NASA Ames Research Center, Moffett Field, methods (analog photoplates or digital photo- CA, USA graphs), photometric (radiometric) spot measure- 3 ASI Science Data Center / INAF - Osservatorio ments and recording digital images by imaging Astronomico di Roma, Rome, Italy photometers, spectrophotometers, or 4 INAF-Osservatorio Astronomico di spectroradiometers. Capodimonte, Naples, Italy The delineation of albedo features on panchro- matic or monochromatic photography is based on the creation of photographic isodensity contours Definition (analog films) or isophotic contours (digital images) separating different categories of gray An albedo feature is a region on the surface of levels of the image. Special terminology has a nonluminous celestial body (e.g., planet, moon, been developed for making standard reference or small body) with distinct brightness (radiance) to the different gray levels of distinguished values or color, i.e., exhibiting observable/mea- albedo features (see “Classification of Albedo surable brightness- or color-contrast relative to its Categories”). Since these photographic density- based brightness scales are in nonlinear Comp. by: Udayasankar Stage: Revises1 Chapter No.: Title Name: EPL_214584 Date:27/2/15 Time:05:23:59 Page Number: 31 Albedo Feature 31 A Albedo Feature, Fig. 1 This image pair illustrates the effects of illumination, or phase A angle, in recognizing different aspects of the same feature (a 200 m diameter crater) on the lunar surface (Plescia 2009). Left: M1046700 19L: incidence angle 50 (low sun), right: M1070 35386L incidence angle 25 (high sun). Scale bar 200 m. LROC Narrow Angle Camera, PIA12916 (NASA/GSFC/ASU) functional relationship with the brightness or The albedo patterns in a terrestrial environ- albedo defined in photometry (radiometry) (see ment correspond to different surface cover clas- “Concept of Albedo”), the term relative albedo ses (vegetation, soil, etc.) having decisive role in contrast is used in such cases, and in all other climate forcing, and their reflective properties ones, when arbitrary scales are used often specific can be measured by satellite-, airborne-, or to the authors or to the research project. The field-measuring systems. photogeological interpretation calls however for Albedo features may or may not correspond to labeling the delineated albedo feature with the relief features; albedo features may not show any albedo values themselves that conform to its topography (e.g., albedo patterns such as ▶ swirls photometrical definition. Therefore, photometric or ▶ dust devil tracks). (radiometric) calibration is carried out. Albedo Albedo patterns are best visible at high sun value ranges from 0 (blackbody) to 1 (ideal (e.g., near full Moon). In contrast, relief features reflector). During classification, typically only are highlighted at low solar altitude angle (high few subtypes are defined: high albedo (bright), incidence angle) (near the terminator line) where intermediate, and low albedo (dark) (if needed, shadows are the longest and emphasize topogra- also very high and/or very low). The general term phy (Figs. 1 and 2). “albedo” in many photogeologic studies refers to relative, snow- or frost-free surface albedo (Prockter et al. 1998). The Concepts of Albedo The term “albedo feature” is used in connec- tion with spatial variation of surface brightness There are several types of albedo concept (often and called sometimes interchangeably as albedo referred as albedo products) used in different markings or albedo patterns. branches of science such as astronomy, remote The term albedo pattern, however, can be used sensing of Earth, climatology and oceanography, in connection with characteristic time variation etc. The detailed mapping of albedo features not of albedo in the sense of signatures of certain only serves the purposes of planetary geology, surface/atmospheric processes. but plays important role in the research of climate Albedo features can be permanent or variable. change of the Earth. Sagan et al. (1972) defined variable features as Different attributes (often more than one) are variable, snow-/frost-free land albedo patterns therefore attached to the term “albedo” to borrow that change with time (Sagan et al. 1972) specific meaning to it, establishing, thus, (▶ dark deposits (Mars) and ▶ wind streak). a precise terminology and making the plain term Comp. by: Udayasankar Stage: Revises1 Chapter No.: Title Name: EPL_214584 Date:27/2/15 Time:05:23:59 Page Number: 32 A 32 Albedo Feature variations can be carried out by using narrow- band albedo or spectral albedo products. The definition of albedo given above implies that the quantification of the incident and reflected radiation power can be made either locally, using surface densities of radiation power, or globally, characterizing the incoming radiation power over the whole surface using surface-integrated values of surface densities, that is, the radiation power values themselves. The albedo of a celestial body as a whole is used in planetology and astronomy or even in calibration procedures of the brightness values belonging to albedo features as well. One may find two versions of such albedo products with their surfaces modeled either as a plain disk or a sphere. Careful distinction should therefore be made, when using those types of albedo inte- Albedo Feature, Fig. 2 Lineaments of the Jovian moon grated to the whole surface of a celestial body, Europa “transform” from albedo features (seen under high solar altitude angle/low incidence angle) into topographic between bond albedo also known as spherical features (ridges) (observed in low sun conditions, near the albedo and the geometric albedo also known as terminator) (Lucchitta et al. 1981). Scale bar ca. 100 km. physical albedo. Also, distinction between the Voyager 2, PIA01504 (NASA/JPL) brightness concepts of a celestial body and that of a surface should be made. The former is in “albedo” ambiguous. Yet, the definition of functional connection to the magnitude of a star albedo, as an instruction of measurement, is gen- and the latter being synonym of the term specific eral and commonly applicable in all specific intensity or radiance. albedo concepts. The mapping of albedo features applies the local characterization, i.e., surface densities of radiation power having the physical dimension Definitions of Albedo of electromagnetic power/m2. Thus, the term “albedo” that is used in connection with albedo According to a commonly accepted formulation, features is defined as a characteristic reflective “Albedo is defined as the ratio of reflected solar quality
Recommended publications
  • Lunar Impact Crater Identification and Age Estimation with Chang’E
    ARTICLE https://doi.org/10.1038/s41467-020-20215-y OPEN Lunar impact crater identification and age estimation with Chang’E data by deep and transfer learning ✉ Chen Yang 1,2 , Haishi Zhao 3, Lorenzo Bruzzone4, Jon Atli Benediktsson 5, Yanchun Liang3, Bin Liu 2, ✉ ✉ Xingguo Zeng 2, Renchu Guan 3 , Chunlai Li 2 & Ziyuan Ouyang1,2 1234567890():,; Impact craters, which can be considered the lunar equivalent of fossils, are the most dominant lunar surface features and record the history of the Solar System. We address the problem of automatic crater detection and age estimation. From initially small numbers of recognized craters and dated craters, i.e., 7895 and 1411, respectively, we progressively identify new craters and estimate their ages with Chang’E data and stratigraphic information by transfer learning using deep neural networks. This results in the identification of 109,956 new craters, which is more than a dozen times greater than the initial number of recognized craters. The formation systems of 18,996 newly detected craters larger than 8 km are esti- mated. Here, a new lunar crater database for the mid- and low-latitude regions of the Moon is derived and distributed to the planetary community together with the related data analysis. 1 College of Earth Sciences, Jilin University, 130061 Changchun, China. 2 Key Laboratory of Lunar and Deep Space Exploration, National Astronomical Observatories, Chinese Academy of Sciences, 100101 Beijing, China. 3 Key Laboratory of Symbol Computation and Knowledge Engineering of Ministry of Education, College of Computer Science and Technology, Jilin University, 130012 Changchun, China. 4 Department of Information Engineering and Computer ✉ Science, University of Trento, I-38122 Trento, Italy.
    [Show full text]
  • Glossary Glossary
    Glossary Glossary Albedo A measure of an object’s reflectivity. A pure white reflecting surface has an albedo of 1.0 (100%). A pitch-black, nonreflecting surface has an albedo of 0.0. The Moon is a fairly dark object with a combined albedo of 0.07 (reflecting 7% of the sunlight that falls upon it). The albedo range of the lunar maria is between 0.05 and 0.08. The brighter highlands have an albedo range from 0.09 to 0.15. Anorthosite Rocks rich in the mineral feldspar, making up much of the Moon’s bright highland regions. Aperture The diameter of a telescope’s objective lens or primary mirror. Apogee The point in the Moon’s orbit where it is furthest from the Earth. At apogee, the Moon can reach a maximum distance of 406,700 km from the Earth. Apollo The manned lunar program of the United States. Between July 1969 and December 1972, six Apollo missions landed on the Moon, allowing a total of 12 astronauts to explore its surface. Asteroid A minor planet. A large solid body of rock in orbit around the Sun. Banded crater A crater that displays dusky linear tracts on its inner walls and/or floor. 250 Basalt A dark, fine-grained volcanic rock, low in silicon, with a low viscosity. Basaltic material fills many of the Moon’s major basins, especially on the near side. Glossary Basin A very large circular impact structure (usually comprising multiple concentric rings) that usually displays some degree of flooding with lava. The largest and most conspicuous lava- flooded basins on the Moon are found on the near side, and most are filled to their outer edges with mare basalts.
    [Show full text]
  • Special Catalogue Milestones of Lunar Mapping and Photography Four Centuries of Selenography on the Occasion of the 50Th Anniversary of Apollo 11 Moon Landing
    Special Catalogue Milestones of Lunar Mapping and Photography Four Centuries of Selenography On the occasion of the 50th anniversary of Apollo 11 moon landing Please note: A specific item in this catalogue may be sold or is on hold if the provided link to our online inventory (by clicking on the blue-highlighted author name) doesn't work! Milestones of Science Books phone +49 (0) 177 – 2 41 0006 www.milestone-books.de [email protected] Member of ILAB and VDA Catalogue 07-2019 Copyright © 2019 Milestones of Science Books. All rights reserved Page 2 of 71 Authors in Chronological Order Author Year No. Author Year No. BIRT, William 1869 7 SCHEINER, Christoph 1614 72 PROCTOR, Richard 1873 66 WILKINS, John 1640 87 NASMYTH, James 1874 58, 59, 60, 61 SCHYRLEUS DE RHEITA, Anton 1645 77 NEISON, Edmund 1876 62, 63 HEVELIUS, Johannes 1647 29 LOHRMANN, Wilhelm 1878 42, 43, 44 RICCIOLI, Giambattista 1651 67 SCHMIDT, Johann 1878 75 GALILEI, Galileo 1653 22 WEINEK, Ladislaus 1885 84 KIRCHER, Athanasius 1660 31 PRINZ, Wilhelm 1894 65 CHERUBIN D'ORLEANS, Capuchin 1671 8 ELGER, Thomas Gwyn 1895 15 EIMMART, Georg Christoph 1696 14 FAUTH, Philipp 1895 17 KEILL, John 1718 30 KRIEGER, Johann 1898 33 BIANCHINI, Francesco 1728 6 LOEWY, Maurice 1899 39, 40 DOPPELMAYR, Johann Gabriel 1730 11 FRANZ, Julius Heinrich 1901 21 MAUPERTUIS, Pierre Louis 1741 50 PICKERING, William 1904 64 WOLFF, Christian von 1747 88 FAUTH, Philipp 1907 18 CLAIRAUT, Alexis-Claude 1765 9 GOODACRE, Walter 1910 23 MAYER, Johann Tobias 1770 51 KRIEGER, Johann 1912 34 SAVOY, Gaspare 1770 71 LE MORVAN, Charles 1914 37 EULER, Leonhard 1772 16 WEGENER, Alfred 1921 83 MAYER, Johann Tobias 1775 52 GOODACRE, Walter 1931 24 SCHRÖTER, Johann Hieronymus 1791 76 FAUTH, Philipp 1932 19 GRUITHUISEN, Franz von Paula 1825 25 WILKINS, Hugh Percy 1937 86 LOHRMANN, Wilhelm Gotthelf 1824 41 USSR ACADEMY 1959 1 BEER, Wilhelm 1834 4 ARTHUR, David 1960 3 BEER, Wilhelm 1837 5 HACKMAN, Robert 1960 27 MÄDLER, Johann Heinrich 1837 49 KUIPER Gerard P.
    [Show full text]
  • Sky and Telescope
    SkyandTelescope.com The Lunar 100 By Charles A. Wood Just about every telescope user is familiar with French comet hunter Charles Messier's catalog of fuzzy objects. Messier's 18th-century listing of 109 galaxies, clusters, and nebulae contains some of the largest, brightest, and most visually interesting deep-sky treasures visible from the Northern Hemisphere. Little wonder that observing all the M objects is regarded as a virtual rite of passage for amateur astronomers. But the night sky offers an object that is larger, brighter, and more visually captivating than anything on Messier's list: the Moon. Yet many backyard astronomers never go beyond the astro-tourist stage to acquire the knowledge and understanding necessary to really appreciate what they're looking at, and how magnificent and amazing it truly is. Perhaps this is because after they identify a few of the Moon's most conspicuous features, many amateurs don't know where Many Lunar 100 selections are plainly visible in this image of the full Moon, while others require to look next. a more detailed view, different illumination, or favorable libration. North is up. S&T: Gary The Lunar 100 list is an attempt to provide Moon lovers with Seronik something akin to what deep-sky observers enjoy with the Messier catalog: a selection of telescopic sights to ignite interest and enhance understanding. Presented here is a selection of the Moon's 100 most interesting regions, craters, basins, mountains, rilles, and domes. I challenge observers to find and observe them all and, more important, to consider what each feature tells us about lunar and Earth history.
    [Show full text]
  • THE STUDY of SATURN's RINGS 1 Thesis Presented for the Degree Of
    1 THE STUDY OF SATURN'S RINGS 1610-1675, Thesis presented for the Degree of Doctor of Philosophy in the Field of History of Science by Albert Van Haden Department of History of Science and Technology Imperial College of Science and Teohnology University of London May, 1970 2 ABSTRACT Shortly after the publication of his Starry Messenger, Galileo observed the planet Saturn for the first time through a telescope. To his surprise he discovered that the planet does.not exhibit a single disc, as all other planets do, but rather a central disc flanked by two smaller ones. In the following years, Galileo found that Sa- turn sometimes also appears without these lateral discs, and at other times with handle-like appendages istead of round discs. These ap- pearances posed a great problem to scientists, and this problem was not solved until 1656, while the solution was not fully accepted until about 1670. This thesis traces the problem of Saturn, from its initial form- ulation, through the period of gathering information, to the final stage in which theories were proposed, ending with the acceptance of one of these theories: the ring-theory of Christiaan Huygens. Although the improvement of the telescope had great bearing on the problem of Saturn, and is dealt with to some extent, many other factors were in- volved in the solution of the problem. It was as much a perceptual problem as a technical problem of telescopes, and the mental processes that led Huygens to its solution were symptomatic of the state of science in the 1650's and would have been out of place and perhaps impossible before Descartes.
    [Show full text]
  • July 2020 in This Issue Online Readers, ALPO Conference November 6-7, 2020 2 Lunar Calendar July 2020 3 Click on Images an Invitation to Join ALPO 3 for Hyperlinks
    A publication of the Lunar Section of ALPO Edited by David Teske: [email protected] 2162 Enon Road, Louisville, Mississippi, USA Recent back issues: http://moon.scopesandscapes.com/tlo_back.html July 2020 In This Issue Online readers, ALPO Conference November 6-7, 2020 2 Lunar Calendar July 2020 3 click on images An Invitation to Join ALPO 3 for hyperlinks. Observations Received 4 By the Numbers 7 Submission Through the ALPO Image Achieve 4 When Submitting Observations to the ALPO Lunar Section 9 Call For Observations Focus-On 9 Focus-On Announcement 10 2020 ALPO The Walter H. Haas Observer’s Award 11 Sirsalis T, R. Hays, Jr. 12 Long Crack, R. Hill 13 Musings on Theophilus, H. Eskildsen 14 Almost Full, R. Hill 16 Northern Moon, H. Eskildsen 17 Northwest Moon and Horrebow, H. Eskildsen 18 A Bit of Thebit, R. Hill 19 Euclides D in the Landscape of the Mare Cognitum (and Two Kipukas?), A. Anunziato 20 On the South Shore, R. Hill 22 Focus On: The Lunar 100, Features 11-20, J. Hubbell 23 Recent Topographic Studies 43 Lunar Geologic Change Detection Program T. Cook 120 Key to Images in this Issue 134 These are the modern Golden Days of lunar studies in a way, with so many new resources available to lu- nar observers. Recently, we have mentioned Robert Garfinkle’s opus Luna Cognita and the new lunar map by the USGS. This month brings us the updated, 7th edition of the Virtual Moon Atlas. These are all wonderful resources for your lunar studies.
    [Show full text]
  • Water on the Moon, III. Volatiles & Activity
    Water on The Moon, III. Volatiles & Activity Arlin Crotts (Columbia University) For centuries some scientists have argued that there is activity on the Moon (or water, as recounted in Parts I & II), while others have thought the Moon is simply a dead, inactive world. [1] The question comes in several forms: is there a detectable atmosphere? Does the surface of the Moon change? What causes interior seismic activity? From a more modern viewpoint, we now know that as much carbon monoxide as water was excavated during the LCROSS impact, as detailed in Part I, and a comparable amount of other volatiles were found. At one time the Moon outgassed prodigious amounts of water and hydrogen in volcanic fire fountains, but released similar amounts of volatile sulfur (or SO2), and presumably large amounts of carbon dioxide or monoxide, if theory is to be believed. So water on the Moon is associated with other gases. Astronomers have agreed for centuries that there is no firm evidence for “weather” on the Moon visible from Earth, and little evidence of thick atmosphere. [2] How would one detect the Moon’s atmosphere from Earth? An obvious means is atmospheric refraction. As you watch the Sun set, its image is displaced by Earth’s atmospheric refraction at the horizon from the position it would have if there were no atmosphere, by roughly 0.6 degree (a bit more than the Sun’s angular diameter). On the Moon, any atmosphere would cause an analogous effect for a star passing behind the Moon during an occultation (multiplied by two since the light travels both into and out of the lunar atmosphere).
    [Show full text]
  • Glossary of Lunar Terminology
    Glossary of Lunar Terminology albedo A measure of the reflectivity of the Moon's gabbro A coarse crystalline rock, often found in the visible surface. The Moon's albedo averages 0.07, which lunar highlands, containing plagioclase and pyroxene. means that its surface reflects, on average, 7% of the Anorthositic gabbros contain 65-78% calcium feldspar. light falling on it. gardening The process by which the Moon's surface is anorthosite A coarse-grained rock, largely composed of mixed with deeper layers, mainly as a result of meteor­ calcium feldspar, common on the Moon. itic bombardment. basalt A type of fine-grained volcanic rock containing ghost crater (ruined crater) The faint outline that remains the minerals pyroxene and plagioclase (calcium of a lunar crater that has been largely erased by some feldspar). Mare basalts are rich in iron and titanium, later action, usually lava flooding. while highland basalts are high in aluminum. glacis A gently sloping bank; an old term for the outer breccia A rock composed of a matrix oflarger, angular slope of a crater's walls. stony fragments and a finer, binding component. graben A sunken area between faults. caldera A type of volcanic crater formed primarily by a highlands The Moon's lighter-colored regions, which sinking of its floor rather than by the ejection of lava. are higher than their surroundings and thus not central peak A mountainous landform at or near the covered by dark lavas. Most highland features are the center of certain lunar craters, possibly formed by an rims or central peaks of impact sites.
    [Show full text]
  • Lick Observatory Records: Photographs UA.036.Ser.07
    http://oac.cdlib.org/findaid/ark:/13030/c81z4932 Online items available Lick Observatory Records: Photographs UA.036.Ser.07 Kate Dundon, Alix Norton, Maureen Carey, Christine Turk, Alex Moore University of California, Santa Cruz 2016 1156 High Street Santa Cruz 95064 [email protected] URL: http://guides.library.ucsc.edu/speccoll Lick Observatory Records: UA.036.Ser.07 1 Photographs UA.036.Ser.07 Contributing Institution: University of California, Santa Cruz Title: Lick Observatory Records: Photographs Creator: Lick Observatory Identifier/Call Number: UA.036.Ser.07 Physical Description: 101.62 Linear Feet127 boxes Date (inclusive): circa 1870-2002 Language of Material: English . https://n2t.net/ark:/38305/f19c6wg4 Conditions Governing Access Collection is open for research. Conditions Governing Use Property rights for this collection reside with the University of California. Literary rights, including copyright, are retained by the creators and their heirs. The publication or use of any work protected by copyright beyond that allowed by fair use for research or educational purposes requires written permission from the copyright owner. Responsibility for obtaining permissions, and for any use rests exclusively with the user. Preferred Citation Lick Observatory Records: Photographs. UA36 Ser.7. Special Collections and Archives, University Library, University of California, Santa Cruz. Alternative Format Available Images from this collection are available through UCSC Library Digital Collections. Historical note These photographs were produced or collected by Lick observatory staff and faculty, as well as UCSC Library personnel. Many of the early photographs of the major instruments and Observatory buildings were taken by Henry E. Matthews, who served as secretary to the Lick Trust during the planning and construction of the Observatory.
    [Show full text]
  • GRAIL-Identified Gravity Anomalies in Oceanus Procellarum: Insight Into 2 Subsurface Impact and Magmatic Structures on the Moon 3 4 Ariel N
    1 GRAIL-identified gravity anomalies in Oceanus Procellarum: Insight into 2 subsurface impact and magmatic structures on the Moon 3 4 Ariel N. Deutscha, Gregory A. Neumannb, James W. Heada, Lionel Wilsona,c 5 6 aDepartment of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 7 02912, USA 8 bNASA Goddard Space Flight Center, Greenbelt, MD 20771, USA 9 cLancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK 10 11 Corresponding author: Ariel N. Deutsch 12 Corresponding email: [email protected] 13 14 Date of re-submission: 5 April 2019 15 16 Re-submitted to: Icarus 17 Manuscript number: ICARUS_2018_549 18 19 Highlights: 20 • Four positive Bouguer gravity anomalies are analyzed on the Moon’s nearside. 21 • The amplitudes of the anomalies require a deep density contrast. 22 • One 190-km anomaly with crater-related topography is suggestive of mantle uplift. 23 • Marius Hills anomalies are consistent with intruded dike swarms. 24 • An anomaly south of Aristarchus has a crater rim and possibly magmatic intrusions. 25 26 Key words: 27 Moon; gravity; impact cratering; volcanism 1 28 Abstract 29 30 Four, quasi-circular, positive Bouguer gravity anomalies (PBGAs) that are similar in diameter 31 (~90–190 km) and gravitational amplitude (>140 mGal contrast) are identified within the central 32 Oceanus Procellarum region of the Moon. These spatially associated PBGAs are located south of 33 Aristarchus Plateau, north of Flamsteed crater, and two are within the Marius Hills volcanic 34 complex (north and south). Each is characterized by distinct surface geologic features suggestive 35 of ancient impact craters and/or volcanic/plutonic activity.
    [Show full text]
  • Lunar Distances Final
    A (NOT SO) BRIEF HISTORY OF LUNAR DISTANCES: LUNAR LONGITUDE DETERMINATION AT SEA BEFORE THE CHRONOMETER Richard de Grijs Department of Physics and Astronomy, Macquarie University, Balaclava Road, Sydney, NSW 2109, Australia Email: [email protected] Abstract: Longitude determination at sea gained increasing commercial importance in the late Middle Ages, spawned by a commensurate increase in long-distance merchant shipping activity. Prior to the successful development of an accurate marine timepiece in the late-eighteenth century, marine navigators relied predominantly on the Moon for their time and longitude determinations. Lunar eclipses had been used for relative position determinations since Antiquity, but their rare occurrences precludes their routine use as reliable way markers. Measuring lunar distances, using the projected positions on the sky of the Moon and bright reference objects—the Sun or one or more bright stars—became the method of choice. It gained in profile and importance through the British Board of Longitude’s endorsement in 1765 of the establishment of a Nautical Almanac. Numerous ‘projectors’ jumped onto the bandwagon, leading to a proliferation of lunar ephemeris tables. Chronometers became both more affordable and more commonplace by the mid-nineteenth century, signaling the beginning of the end for the lunar distance method as a means to determine one’s longitude at sea. Keywords: lunar eclipses, lunar distance method, longitude determination, almanacs, ephemeris tables 1 THE MOON AS A RELIABLE GUIDE FOR NAVIGATION As European nations increasingly ventured beyond their home waters from the late Middle Ages onwards, developing the means to determine one’s position at sea, out of view of familiar shorelines, became an increasingly pressing problem.
    [Show full text]
  • Lunar Observing Report February 12Th 2011- Lichfield - 66% Waxing Gibbous
    Lunar Observing Report February 12th 2011- Lichfield - 66% Waxing Gibbous It was with some trepidation that I ventured out on Saturday after my last experience with the new Televue 3.7mm Ethos. Would I suffer the same problems of kidney beaning blackouts and that horrid yellow/red ‘flaming halo’....? I’d had some thought provoking responses from far more 1 experienced observers to my query on the American forum; ‘Cloudy Nights’. Suggestions ranged from making sure the eyepiece was seated correctly in the diagonal, atmospheric distorsions, faulty eyepiece etc, yet the most common theme appeared to be the link between my scopes f/ratio (greater than f7), a small (less than) 0.5mm exit pupil, ultra wide (110-FOV) with a large eye lens - as well as trying to view a bright full moon too! As one commentator stated, ”the brightness of the full moon causes your eye's pupil to constrict, which makes it all too easy to sample only a portion of the (already small), exit pupil with your eye pupil (and interfering with eye placement), especially when you're looking 55 degrees off axis! Before trying to look around, I'd suggest trying to look on axis and letting your peripheral vision soak in the 110 degree field.” Also, “diameter of exit pupil figures are mostly consigned into side-to-side tolerance for eye positioning, and typically the manifestation is not so much blackouts but dimming of the view as one clips part of the light for any given point by letting the eye wander too much to one side or the other.
    [Show full text]