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| | AllRefer.com - Pleistocene epoch (Geology And Oceanography) - Encyclopedia |
 | | You are here : AllRefer.com > Reference > Encyclopedia > Geology And Oceanography > Pleistocene epoch | | | More articles from AllRefer Reference on Pleistocene epoch | | | According to a classification that considered its deposits to have been formed by the biblical great flood, the epoch was originally called the Quaternary. |
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http://reference.allrefer.com/encyclopedia/P/Pleistoc.html
(248 words)
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| | Epoch - Wikipedia, the free encyclopedia |
| | an epoch date, an instant of origin chosen as the reference from which time is measured in a calendar era or in a computer system. | | | Epoch (comics), a supervillian written in DC comics also known as the Lord of Time | | | an epoch (astronomy), a moment in time for which celestial coordinates or orbital elements are specified. |
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http://www.wikipedia.org/wiki/Epoch
(184 words)
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| | epoch - OneLook Dictionary Search |
| | Words similar to epoch: era, age, date of reference, period, more... | | | noun: (astronomy) the precise date that is the point of reference for which information (as coordinates of a celestial body) is referred | | | Phrases that include epoch: epoch making, pleistocene epoch, holocene epoch, miocene epoch, oligocene epoch, more... |
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http://www.onelook.com/cgi-bin/cgiwrap/bware/dofind.cgi?word=epoch
(304 words)
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| | epoch (HyperDic hyper-dictionary) |
| | (astronomy) the precise date that is the point of reference for which information (as coordinates of a celestial body) is referred. | | | (astronomy) the precise date that is the point of reference for which information (as coordinates of a celestial body) is referred | | | Holocene, Holocene epoch, Recent, Recent epoch; Pleistocene, Pleistocene epoch, Glacial epoch; Pliocene, Pliocene epoch; Miocene, Miocene epoch; Oligocene, Oligocene epoch; Eocene, Eocene epoch; Paleocene, Paleocene epoch |
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http://www.hyperdic.net/dic/epoch.htm
(162 words)
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| | refsys_gb |
| | The reference frame of coordinates determined from point positioning will be identical to the reference frame of the satellite orbits, which is used to determine the satellite positions at signal emission time. | | | In addition, each of these systems, consisting of a set of theoretical definitions, can only be used in practice if it has an associated reference frame. | | | If the coordinates of the reference stations refer to a different reference frame than the satellite orbits, then the relation between both references needs to be known. |
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http://www.gps.oma.be/gb/refsys_gb.htm
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| | refsys_gb |
| | The reference frame of coordinates determined from point positioning will be identical to the reference frame of the satellite orbits, which is used to determine the satellite positions at signal emission time. | | | In addition, each of these systems, consisting of a set of theoretical definitions, can only be used in practice if it has an associated reference frame. | | | If the coordinates of the reference stations refer to a different reference frame than the satellite orbits, then the relation between both references needs to be known. |
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http://www.gps.oma.be/gb/refsys_gb.htm
(162 words)
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| | J2000.0 - Enpsychlopedia |
| | Since the right ascension and declination of stars are constantly changing due to precession, (and, for relatively nearby stars due to proper motion), astronomers always specify these with reference to a particular epoch. | | | Novices are sometimes confused by finding that the Earth's rotational North pole does not point quite at the J2000 celestial pole at the epoch J2000.0; the reason is that the true pole of epoch suffers nutation ("is nutated") away from the mean one. | | | The earlier epoch that was in standard use was the B1950.0 epoch. |
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http://www.grohol.com/psypsych/wiki/J2000
(162 words)
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| | Ordnance Survey Ireland :: Geodetic services :: Overview :: GPS Reference Systems |
| | Thus different co-ordinate systems are established, within the defining reference frame, linked to the epoch of the observation, and transformations have been defined between them, which move positions from those determined at the time of observations to a common system at a defined epoch. | | | WGS84 is a geocentric reference ellipsoid and a geodetic datum, in that it defines the centre of mass of the earth as its origin, and the direction of the earth's axis as the minor axis of the reference ellipsoid. | | | The adoption of regional or local reference ellipsoids results in different positions for the same point along common boundaries between two different regions. |
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http://www.osi.ie/gps/overview/gps.asp
(918 words)
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| | EUREF Permanent GPS Network - Data & Products - Products |
| | The switch from one realization to its successor (for example from ITRF94 to ITRF96) is done simultaneously with the update of the reference frame used for the compution of the IGS orbits. | | | The weekly combined EUREF solution, available in the ITRFxx, at the epoch of observation can be linked to the European Terrestrial Reference System ( ETRS89) by applying the " Guidelines for Reference Frame Fixing ". | | | This guarantees the consistency between the reference frame used for the orbits (which are kept fixed for all EUREF computations) and the constraints on the coordinates. |
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http://www.epncb.oma.be/_dataproducts/products
(918 words)
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| | EUREF Permanent GPS Network - Data & Products - Products |
| | The switch from one realization to its successor (for example from ITRF94 to ITRF96) is done simultaneously with the update of the reference frame used for the compution of the IGS orbits. | | | The weekly combined EUREF solution, available in the ITRFxx, at the epoch of observation can be linked to the European Terrestrial Reference System ( ETRS89) by applying the " Guidelines for Reference Frame Fixing ". | | | This guarantees the consistency between the reference frame used for the orbits (which are kept fixed for all EUREF computations) and the constraints on the coordinates. |
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http://www.epncb.oma.be/_dataproducts/products
(918 words)
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| | World Geodetic System 1984 - Background |
| | ETRS89 is a geocentric reference system fixed to the stable part of the European plate and identical to ITRS89 at the epoch 1989.0, with geographical co-ordinates based on the GRS80 ellipsoid. | | | It was agreed that the high accuracy geodetic reference ETRF be used as the realisation of WGS 84 for civil aviation in Europe (refer 4.1.3 in the EUROCONTROL Standard 'Surveying of Navigation Facilities'). | | | A geodetic datum transformation is a mathematical rule used to transform surveyed coordinates given in Reference Frame 1 into coordinates given in Reference Frame 2. |
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http://www.wgs84.com/wgs84/wgs84.htm
(1736 words)
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| | World Geodetic System 1984 - Background |
| | ETRS89 is a geocentric reference system fixed to the stable part of the European plate and identical to ITRS89 at the epoch 1989.0, with geographical co-ordinates based on the GRS80 ellipsoid. | | | It was agreed that the high accuracy geodetic reference ETRF be used as the realisation of WGS 84 for civil aviation in Europe (refer 4.1.3 in the EUROCONTROL Standard 'Surveying of Navigation Facilities'). | | | A geodetic datum transformation is a mathematical rule used to transform surveyed coordinates given in Reference Frame 1 into coordinates given in Reference Frame 2. |
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http://www.wgs84.com/wgs84/wgs84.htm
(1736 words)
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| | SPK Required Reading |
| | In the SPK system times are specified as a count of seconds past a particular epoch---the epoch of the J2000 reference frame. | | | It is important to note that the epoch must be that of periapsis passage. | | | A state is obtained from a Type 5 segment for any epoch that is within the bounds of that segment by propagating the discrete states to the specified epoch according to the laws of two body motion. |
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http://www.gps.caltech.edu/~marsdata/req/spk.html
(15030 words)
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| | 10.4 PRECESS - Astronomical Coordinate Conversion |
| | The FK4 system is tied to the equatorial coordinate system for Besselian epoch B1950.0, while the more accurate FK5 system is tied to the equatorial system for Julian epoch J2000.0. | | | This definition depends on epoch because of precession; its practical implementation also depends on the set of fundamental reference stars used to measure coordinates. | | | Ecliptic coordinates are weakly epoch dependent, so the user may wish to use a specific epoch to define the orbital plane rather than the default B1950.0. |
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http://ledas-cxc.star.le.ac.uk/udocs/docs/PG/html/node76.html
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| | TYCHO2 - Tycho-2 Catalog of the 2.5 Million Brightest Stars |
| | Mean satellite observation epoch ~J1991.5 Epoch of the Tycho-2 Catalogue J2000.0 Reference system ICRS coincidence with ICRS (1) +/-0.6 mas deviation from inertial (1) +/-0.25 mas/yr Number of entries 2,539,913 Astrometric standard errors (2) V_T < 9 mag 7 mas all stars, positions 60 mas all stars, proper motions 2.5 mas/yr Photometric std. | | | The declination of the star, in the ICRS system (J2000 equinox), at the epoch specified by the parameter dec_epoch, and given in decimal degrees. | | | All positions in the original Tycho-2 Catalog were given in the ICRS system (which is essentially J2000 equator), with the parameters mean_ra and mean_dec being the position at epoch 2000.0 while the parameters observed_ra and observed_dec being the position at the epochs RA_epoch and Dec_epoch, respectively, when observed by Tycho. |
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http://starchild.gsfc.nasa.gov/W3Browse/star-catalog/tycho2.html
(2365 words)
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| | Epoch date - Wikipedia, the free encyclopedia |
| | In telecommunications, an epoch date is a date in history chosen as the reference date from which time is measured. | | | Another famous epoch date is January 1, 1970, the date from which Unix time is measured. | | | One example of an epoch date is the beginning instant of January 1, 1900, Universal Time, for Transmission Control Protocol/Internet Protocol (TCP/IP). |
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http://www.wikipedia.org/wiki/Epoch_date
(123 words)
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| | Whitehead and Newton on Space and Time Structure |
| | Uniform rectilinear motion relative to some physical system is the classic example; such motion may be altered or terminated altogether by imparting motion not to the material object said to be in motion but to the physical system that is used as a frame of reference. | | | The uniformity of motion along a path in absolute space, or the lack of it, would require reference in like manner to the one privileged, or "absolute," frame of reference, that is, absolute time. | | | The laws of motion are to be stated, then, in terms of the one privileged, or "absolute," frame of reference, that is, absolute space. |
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http://www.religion-online.org/showarticle.asp?title=2433
(8917 words)
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| | Sect_2.1.4 |
| | The Julian Date (JD) defines the number mean solar days (each of which is 86400 SI second in length) elapsed since the epoch 1.5 (midday) January, 4713 B.C. The Modified Julian Date (MJD) is obtained by subtracting 2400000.5 from the JD. | | | The WGS84 system is the most widely used global reference system because it is the system in which the GPS satellite coordinates are expressed in the Navigation Message (section 3.3.3). | | | Reference systems are periodically redefined, for various reasons, such as when the primary tracking technology changes (for example when the TRANSIT system was superseded by GPS), or if the configuration of ground stations alters radically enough to justify a recomputation of the global datum coordinates. |
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http://www.gmat.unsw.edu.au/snap/gps/gps_survey/chap2/214.htm
(1885 words)
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| | Sect_2.1.4 |
| | The Julian Date (JD) defines the number mean solar days (each of which is 86400 SI second in length) elapsed since the epoch 1.5 (midday) January, 4713 B.C. The Modified Julian Date (MJD) is obtained by subtracting 2400000.5 from the JD. | | | The WGS84 system is the most widely used global reference system because it is the system in which the GPS satellite coordinates are expressed in the Navigation Message (section 3.3.3). | | | Reference systems are periodically redefined, for various reasons, such as when the primary tracking technology changes (for example when the TRANSIT system was superseded by GPS), or if the configuration of ground stations alters radically enough to justify a recomputation of the global datum coordinates. |
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http://www.gmat.unsw.edu.au/snap/gps/gps_survey/chap2/214.htm
(1885 words)
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| | SLA_FK45Z - FK4 to FK5, no P.M. or Parallax |
| | Because such a star has, in general, a non-zero proper motion in the FK4 system, the routine requires the epoch at which the position in the FK4 system was determined. | | | The epoch BEPOCH is strictly speaking Besselian, but if a Julian epoch is supplied the result will be affected only to a negligible extent. | | | The method is from appendix 2 of reference 1, but using the constants of reference 4. |
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http://www.hartrao.ac.za/nccsdoc/slalib/sun67.htx/node105.html
(1885 words)
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| | Derivation of Coords |
| | One of these reference frames was instituted by the International Earth Rotation Service (IERS); it is called the IERS Terrestrial Reference Frame (ITRF). | | | For several of the older CORS, NGS has also computed ITRF positions and velocities that are consistent with the IERS solution known as ITRF94 (epoch 1996.0) and/or ITRF positions and velocities consistent with the IERS solution known as ITRF93 (epoch 1995.0). | | | The other reference frame is the North American Datum of 1983 (NAD 83). |
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http://www.ngs.noaa.gov/CORS/Derivation.html
(1885 words)
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| | ccmap |
| | In this case the reference point coordinates are assumed to be equatorial FK4 coordinates at the epoch specified by EPOCH. | | | In the latter case the coordinate system is assumed to be equatorial FK4 at equinox EPOCH. | | | The standard coordinates xi and eta are computed from the input celestial coordinates using the sky projection geometry projection and the celestial coordinates of the projection reference point set by the user. |
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http://stsdas.stsci.edu/cgi-bin/gethelp.cgi?ccmap
(4456 words)
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| | ITRF2000: A new release of the International Terrestrial Reference Frame for earth science applications |
| | For the first time in the history of the International Terrestrial Reference Frame, the ITRF2000 combines unconstrained space geodesy solutions that are free from any tectonic plate motion model. | | | Minimum constraints are applied to these solutions solely in order to define the underlying terrestrial reference frame (TRF). | | | Its orientation is aligned to the ITRF97 at epoch 1997.0, and its orientation time evolution follows, conventionally, that of the no-net-rotation NNR-NUVEL-1A model. |
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http://www.agu.org/pubs/crossref/2002/2001JB000561.shtml
(4456 words)
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| | Precession and Nutation |
| | Hapgood (1997) gives only the first order transformation between epoch of J2000.0 and epoch of date which is a reduction of the above formulae and also given to higher precision in [A. | | | The obliquity of the ecliptic at epoch J2000.0 with respect to the mean equator at epoch J2000.0 is given by [A. | | | The two fundamental celestial reference systems used in heliospheric science are the ecliptic system defined by the mean orbit of the Earth at J2000.0 and the equatorial system defined by the mean orientation of the Earth equator at J2000.0 (see Fig. |
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http://www.space-plasma.qmw.ac.uk/heliocoords/systems2art/node3.html
(418 words)
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| | TIME-BINDING: Second Paper |
| | Perhaps the clarifications on the private level do not clear up the public, or scientific, level which represents the creeds of a certain epoch, and so might be in agreement with the general development of the race. | | | It is interesting to note that "epoch-making discoveries" are seldom if ever isolated; usually they come in bundles, being discovered by several individuals independently; they are "in the air," as we sayperhaps they are in the protoplasm more than in the air. | | | We should not be surprised that, under such circumstances, the "motional" and "emotional" systems of science and philosophy, systems which make rigorous rationality impossible, are the remains of the pre-human, pre-cortex epoch of development. |
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http://www.esgs.org/uk/art/ak8.htm
(16725 words)
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| | Kristensen_and_Gammelgaard_1993 |
| | ******************************************************************************** begin general UPDATE........: - REFERENCE.....: Kristensen and Gammelgaard (1993) end ******************************************************************************** include general OBJECT........: 51 Nemausa OBSERVING TIME: 1990 Sep 07.0 PHOT. | | | GEOMETRY......: system: J2000.0 ecliptic epoch: 2448141.5 (1990 Sep 7.0) Earth: 0.970003 -0.273426 0.000002 0.004388 0.016495 0.000000 object: 2.069404 -1.375060 0.217239 0.006238 0.008422 -0.001547 ASPECT DATA...: 2.4941 1.5715 11.76 314.94 7.95 2448141.50000 J2000.0 DATA: ================----------------================----------------================ include general OBJECT........: 51 Nemausa OBSERVING TIME: 1990 Sep 08.0 PHOT. | | | GEOMETRY......: system: J2000.0 ecliptic epoch: 2448142.5 (1990 Sep 8.0) Earth: 0.974250 -0.256893 0.000002 0.004107 0.016571 0.000000 object: 2.075622 -1.366626 0.215690 0.006199 0.008448 -0.001551 ASPECT DATA...: 2.4945 1.5783 12.13 314.78 7.86 2448142.50000 J2000.0 DATA: ================----------------================----------------================ include general OBJECT........: 51 Nemausa OBSERVING TIME: 1990 Sep 09.0 PHOT. |
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http://www.psi.edu/pds/astdata03/apc/Atlas5/K/Kristensen_and_Gammelgaard_1993
(730 words)
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| | GEOLOGICAL TIME PERIODS |
| | Triassic first epoch of the Mesozoic period, lasting for 45 million years during which time the reptiles flourished; from Latin trias or 'triad', with reference to its three divisions. | | | Era a period of time considered to possess a certain distinctive character; there are four distinct eras of geological time, the Palaeozoic, Mesozoic, Tertiary and Pleistocene, each of which are divided into a number of epochs; from Latin aera 'counters'. | | | Epoch a point in time which marks the beginning of a distinct period in history, in geology, a unit of geological time during which a series of sedimentary rocks are deposited; from New Latin epocha from Greek epokhe 'cessation'. |
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http://www.roman-britain.org/chase/_geological.htm
(1120 words)
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| | Astron. Astrophys. 321, 660-664 (1997) |
| | In the third decade of this century astronomers of the Pulkovo observatory proposed a programme for determination of absolute proper motions of stars using faint galaxies as an inertial reference frame (Deutsch 1952). | | | Special methods developed at Golosiiv observatory including the selection of kinematically homogeneous group of reference stars, the removal of systematic errors in proper motions (especially magnitude equation), and the calibration of stellar magnitudes were applied to compile the general catalogue. | | | For the second epoch only Golosiiv (Kyiv) and Pulkovo observatories have completely finished the observations whereas the Moscow, Tashkent, and Shanghai observatories have almost finished them. |
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http://aa.springer.de/papers/7321002/2300660/sc2.htm
(644 words)
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