JULIAN DATE (JD) Case May Be
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Ast 443 / Phy 517
AST 443 / PHY 517 Astronomical Observing Techniques Prof. F.M. Walter I. The Basics The 3 basic measurements: • WHERE something is • WHEN something happened • HOW BRIGHT something is Since this is science, let’s be quantitative! Where • Positions: – 2-dimensional projections on celestial sphere (q,f) • q,f are angular measures: radians, or degrees, minutes, arcsec – 3-dimensional position in space (x,y,z) or (q, f, r). • (x,y,z) are linear positions within a right-handed rectilinear coordinate system. • R is a distance (spherical coordinates) • Galactic positions are sometimes presented in cylindrical coordinates, of galactocentric radius, height above the galactic plane, and azimuth. Angles There are • 360 degrees (o) in a circle • 60 minutes of arc (‘) in a degree (arcmin) • 60 seconds of arc (“) in an arcmin There are • 24 hours (h) along the equator • 60 minutes of time (m) per hour • 60 seconds of time (s) per minute • 1 second of time = 15”/cos(latitude) Coordinate Systems "What good are Mercator's North Poles and Equators Tropics, Zones, and Meridian Lines?" So the Bellman would cry, and the crew would reply "They are merely conventional signs" L. Carroll -- The Hunting of the Snark • Equatorial (celestial): based on terrestrial longitude & latitude • Ecliptic: based on the Earth’s orbit • Altitude-Azimuth (alt-az): local • Galactic: based on MilKy Way • Supergalactic: based on supergalactic plane Reference points Celestial coordinates (Right Ascension α, Declination δ) • δ = 0: projection oF terrestrial equator • (α, δ) = (0,0): -
A Study of Ancient Khmer Ephemerides
A study of ancient Khmer ephemerides François Vernotte∗ and Satyanad Kichenassamy** November 5, 2018 Abstract – We study ancient Khmer ephemerides described in 1910 by the French engineer Faraut, in order to determine whether they rely on observations carried out in Cambodia. These ephemerides were found to be of Indian origin and have been adapted for another longitude, most likely in Burma. A method for estimating the date and place where the ephemerides were developed or adapted is described and applied. 1 Introduction Our colleague Prof. Olivier de Bernon, from the École Française d’Extrême Orient in Paris, pointed out to us the need to understand astronomical systems in Cambo- dia, as he surmised that astronomical and mathematical ideas from India may have developed there in unexpected ways.1 A proper discussion of this problem requires an interdisciplinary approach where history, philology and archeology must be sup- plemented, as we shall see, by an understanding of the evolution of Astronomy and Mathematics up to modern times. This line of thought meets other recent lines of research, on the conceptual evolution of Mathematics, and on the definition and measurement of time, the latter being the main motivation of Indian Astronomy. In 1910 [1], the French engineer Félix Gaspard Faraut (1846–1911) described with great care the method of computing ephemerides in Cambodia used by the horas, i.e., the Khmer astronomers/astrologers.2 The names for the astronomical luminaries as well as the astronomical quantities [1] clearly show the Indian origin ∗F. Vernotte is with UTINAM, Observatory THETA of Franche Comté-Bourgogne, University of Franche Comté/UBFC/CNRS, 41 bis avenue de l’observatoire - B.P. -
How Long Is a Year.Pdf
How Long Is A Year? Dr. Bryan Mendez Space Sciences Laboratory UC Berkeley Keeping Time The basic unit of time is a Day. Different starting points: • Sunrise, • Noon, • Sunset, • Midnight tied to the Sun’s motion. Universal Time uses midnight as the starting point of a day. Length: sunrise to sunrise, sunset to sunset? Day Noon to noon – The seasonal motion of the Sun changes its rise and set times, so sunrise to sunrise would be a variable measure. Noon to noon is far more constant. Noon: time of the Sun’s transit of the meridian Stellarium View and measure a day Day Aday is caused by Earth’s motion: spinning on an axis and orbiting around the Sun. Earth’s spin is very regular (daily variations on the order of a few milliseconds, due to internal rearrangement of Earth’s mass and external gravitational forces primarily from the Moon and Sun). Synodic Day Noon to noon = synodic or solar day (point 1 to 3). This is not the time for one complete spin of Earth (1 to 2). Because Earth also orbits at the same time as it is spinning, it takes a little extra time for the Sun to come back to noon after one complete spin. Because the orbit is elliptical, when Earth is closest to the Sun it is moving faster, and it takes longer to bring the Sun back around to noon. When Earth is farther it moves slower and it takes less time to rotate the Sun back to noon. Mean Solar Day is an average of the amount time it takes to go from noon to noon throughout an orbit = 24 Hours Real solar day varies by up to 30 seconds depending on the time of year. -
Sidereal Time 1 Sidereal Time
Sidereal time 1 Sidereal time Sidereal time (pronounced /saɪˈdɪəri.əl/) is a time-keeping system astronomers use to keep track of the direction to point their telescopes to view a given star in the night sky. Just as the Sun and Moon appear to rise in the east and set in the west, so do the stars. A sidereal day is approximately 23 hours, 56 minutes, 4.091 seconds (23.93447 hours or 0.99726957 SI days), corresponding to the time it takes for the Earth to complete one rotation relative to the vernal equinox. The vernal equinox itself precesses very slowly in a westward direction relative to the fixed stars, completing one revolution every 26,000 years approximately. As a consequence, the misnamed sidereal day, as "sidereal" is derived from the Latin sidus meaning "star", is some 0.008 seconds shorter than the earth's period of rotation relative to the fixed stars. The longer true sidereal period is called a stellar day by the International Earth Rotation and Reference Systems Service (IERS). It is also referred to as the sidereal period of rotation. The direction from the Earth to the Sun is constantly changing (because the Earth revolves around the Sun over the course of a year), but the directions from the Earth to the distant stars do not change nearly as much. Therefore the cycle of the apparent motion of the stars around the Earth has a period that is not quite the same as the 24-hour average length of the solar day. Maps of the stars in the night sky usually make use of declination and right ascension as coordinates. -
Governing the Time of the World Written by Tim Stevens
Governing the Time of the World Written by Tim Stevens This PDF is auto-generated for reference only. As such, it may contain some conversion errors and/or missing information. For all formal use please refer to the official version on the website, as linked below. Governing the Time of the World https://www.e-ir.info/2016/08/07/governing-the-time-of-the-world/ TIM STEVENS, AUG 7 2016 This is an excerpt from Time, Temporality and Global Politics – an E-IR Edited Collection. Available now on Amazon (UK, USA, Ca, Ger, Fra), in all good book stores, and via a free PDF download. Find out more about E-IR’s range of open access books here Recent scholarship in International Relations (IR) is concerned with how political actors conceive of time and experience temporality and, specifically, how these ontological and epistemological considerations affect political theory and practice (Hutchings 2008; Stevens 2016). Drawing upon diverse empirical and theoretical resources, it emphasises both the political nature of ‘time’ and the temporalities of politics. This chronopolitical sensitivity augments our understanding of international relations as practices whose temporal dimensions are as fundamental to their operations as those revealed by more established critiques of spatiality, materiality and discourse (see also Klinke 2013). This transforms our understanding of time as a mere backdrop to ‘history’ and other core concerns of IR (Kütting 2001) and provides opportunities to reflect upon the constitutive role of time in IR theory itself (Berenskoetter 2011; Hom and Steele 2010; Hutchings 2007; McIntosh 2015). One strand of IR scholarship problematises the historical emergence of a hegemonic global time that subsumed within it local and indigenous times to become the time by which global trade and communications are transacted (Hom 2010, 2012). -
1777 - Wikipedia, the Free Encyclopedia
1777 - Wikipedia, the free encyclopedia https://en.wikipedia.org/wiki/1777 From Wikipedia, the free encyclopedia 1777 (MDCCLXXVII) was a common year starting Millennium: 2nd millennium on Wednesday (dominical letter E) of the Gregorian Centuries: 17th century – 18th century – 19th century calendar and a common year starting on Sunday Decades: 1740s 1750s 1760s – 1770s – 1780s 1790s 1800s (dominical letter A) of the Julian calendar, the 1777th year of the Common Era (CE) and Anno Domini (AD) Years: 1774 1775 1776 – 1777 – 1778 1779 1780 designations, the 777th year of the 2nd millennium, the 77th year of the 18th century, and the 8th year of the 1770s decade. 1777 by topic: Note that the Julian day for 1777 is 11 calendar days difference, which continued to be used from 1582 until the complete Arts and Sciences conversion of the Gregorian calendar was entirely done in 1929. Archaeology – Architecture – Art – Literature (Poetry) – Music – Science Countries Canada –Denmark – France – Great Britain – January–June Ireland – Norway – Scotland –Sweden – United States January 2 – American Revolutionary War – Battle of the Assunpink Creek: American general George Washington's Lists of leaders army defeats the British under Lieutenant General Charles Colonial governors – State leaders Cornwallis in a second battle at Trenton, New Jersey. Birth and death categories January 3 – American Revolutionary War – Battle of Princeton: American general George Washington's army Births – Deaths again defeats the British. Establishments and disestablishments January 12 – Mission Santa Clara de Asís is founded in what categories is now Santa Clara, California. Establishments – Disestablishments January 15 – Vermont declares its independence from New York, becoming the Vermont Republic, an independent Works category country, a status it retains until it joins the United States as Works the 14th state in 1791. -
TIMEDATE Time and Date Utilities
§1 TIMEDATE INTRODUCTION 1 1. Introduction. TIMEDATE Time and Date Utilities by John Walker http://www.fourmilab.ch/ This program is in the public domain. This program implements the systemtime class, which provides a variety of services for date and time quantities which use UNIX time t values as their underlying data type. One can set these values from strings, edit them to strings, convert to and from Julian dates, determine the sidereal time at Greenwich for a given moment, and compute properties of the Moon and Sun including geocentric celestial co-ordinates, distance, and phases of the Moon. A utility angle class provides facilities used by the positional astronomy services in systemtime, but may prove useful in its own right. h timedate_test.c 1 i ≡ #define REVDATE "2nd February 2002" See also section 32. 2 PROGRAM GLOBAL CONTEXT TIMEDATE §2 2. Program global context. #include "config.h" /∗ System-dependent configuration ∗/ h Preprocessor definitions i h Application include files 4 i h Class implementations 5 i 3. We export the class definitions for this package in the external file timedate.h that programs which use this library may include. h timedate.h 3 i ≡ #ifndef TIMEDATE_HEADER_DEFINES #define TIMEDATE_HEADER_DEFINES #include <stdio.h> #include <math.h> /∗ Make sure math.h is available ∗/ #include <time.h> #include <assert.h> #include <string> #include <stdexcept> using namespace std; h Class definitions 6 i #endif 4. The following include files provide access to external components of the program not defined herein. h Application include files 4 i ≡ #include "timedate.h" /∗ Class definitions for this package ∗/ This code is used in section 2. -
Developing a Critical Horology to Rethink the Potential of Clock Time’ in New Formations (Special Issue: Timing Transformations)
This is the final accepted version of this article. Bastian, M. (forthcoming) ‘Liberating clocks: developing a critical horology to rethink the potential of clock time’ in New Formations (Special Issue: Timing Transformations). Liberating clocks: developing a critical horology to rethink the potential of clock time Michelle Bastian [email protected] Introduction When trying to imagine a new time, a transformed time, a way of living time that is inclusive, sustainable or socially-just – a liberatory time – it is unlikely that a clock will spring to mind. If anything, the clock has become the symbol of all that 1 has gone wrong with our relationship to time. This general mistrust of the clock is well-captured by literary theorist Jesse Matz who observes: Clock time was the false metric against which Henri Bergson and others defined the truth of human time. Modernists made clocks the target of their iconoclasm, staging clocks’ destruction (smashing watches, like Quentin in The Sound and the Fury [1929]) or (like Dali) just melting away, and cultural theorists before and after Foucault have founded cultural critique on the premise that clock time destroys humanity.1 Thus, across a wide range of cultural forms, including philosophy, cultural theory, literature and art, the figure of the clock has drawn suspicion, censure and outright hostility. When we compare this to attitudes towards maps however – which are often thought of as spatial counterparts to clocks – we find a remarkably differently picture. While maps have 1 Jesse Matz, 'How to Do Time with Texts', American Literary History, 21, 4 (2009), 836-44, quotation p836. -
THE PHYSICS of TIMLESSNESS Dr
Cosmos and History: The Journal of Natural and Social Philosophy, vol. 14, no. 2, 2018 THE PHYSICS OF TIMLESSNESS Dr. Varanasi Ramabrahmam ABSTRACT: The nature of time is yet to be fully grasped and finally agreed upon among physicists, philosophers, psychologists and scholars from various disciplines. Present paper takes clue from the known assumptions of time as - movement, change, becoming - and the nature of time will be thoroughly discussed. The real and unreal existences of time will be pointed out and presented. The complex number notation of nature of time will be put forward. Natural scientific systems and various cosmic processes will be identified as constructing physical form of time and the physical existence of time will be designed. The finite and infinite forms of physical time and classical, quantum and cosmic times will be delineated and their mathematical constructions and loci will be narrated. Thus the physics behind time-construction, time creation and time-measurement will be given. Based on these developments the physics of Timelessness will be developed and presented. KEYWORDS: physical time, psychological time, finite and infinite times, scalar and vector times, Classical, quantum and cosmic times, timelessness, movement, change, becoming INTRODUCTION: “Our present picture of physical reality, particularly in relation to the nature of time, is due for a grand shake-up—even greater, perhaps, than that which has already been provided by present-day relativity and quantum mechanics” [1]. Time is considered as www.cosmosandhistory.org 1 COSMOS AND HISTORY 2 one of the fundamental quantities in physics. Second, which is the duration of 9,192,631,770 cesium-133 atomic oscillations, is the unit. -
Tidal Datums and Their Applications
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Center for Operational Oceanographic Products and Services TIDAL DATUMS AND THEIR APPLICATIONS NOAA Special Publication NOS CO-OPS 1 NOAA Special Publication NOS CO-OPS 1 TIDAL DATUMS AND THEIR APPLICATIONS Silver Spring, Maryland June 2000 noaa National Oceanic and Atmospheric Administration U.S. DEPARTMENT OF COMMERCE National Ocean Service Center for Operational Oceanographic Products and Services Center for Operational Oceanographic Products and Services National Ocean Service National Oceanic and Atmospheric Administration U.S. Department of Commerce The National Ocean Service (NOS) Center for Operational Oceanographic Products and Services (CO-OPS) collects and distributes observations and predictions of water levels and currents to ensure safe, efficient and environmentally sound maritime commerce. The Center provides the set of water level and coastal current products required to support NOS’ Strategic Plan mission requirements, and to assist in providing operational oceanographic data/products required by NOAA’s other Strategic Plan themes. For example, CO-OPS provides data and products required by the National Weather Service to meet its flood and tsunami warning responsibilities. The Center manages the National Water Level Observation Network (NWLON) and a national network of Physical Oceanographic Real-Time Systems (PORTSTM) in major U.S. harbors. The Center: establishes standards for the collection and processing of water level and current data; collects and documents user requirements which serve as the foundation for all resulting program activities; designs new and/or improved oceanographic observing systems; designs software to improve CO-OPS’ data processing capabilities; maintains and operates oceanographic observing systems; performs operational data analysis/quality control; and produces/disseminates oceanographic products. -
TIME 1. Introduction 2. Time Scales
TIME 1. Introduction The TCS requires access to time in various forms and accuracies. This document briefly explains the various time scale, illustrate the mean to obtain the time, and discusses the TCS implementation. 2. Time scales International Atomic Time (TIA) is a man-made, laboratory timescale. Its units the SI seconds which is based on the frequency of the cesium-133 atom. TAI is the International Atomic Time scale, a statistical timescale based on a large number of atomic clocks. Coordinated Universal Time (UTC) – UTC is the basis of civil timekeeping. The UTC uses the SI second, which is an atomic time, as it fundamental unit. The UTC is kept in time with the Earth rotation. However, the rate of the Earth rotation is not uniform (with respect to atomic time). To compensate a leap second is added usually at the end of June or December about every 18 months. Also the earth is divided in to standard-time zones, and UTC differs by an integral number of hours between time zones (parts of Canada and Australia differ by n+0.5 hours). You local time is UTC adjusted by your timezone offset. Universal Time (UT1) – Universal time or, more specifically UT1, is counted from 0 hours at midnight, with unit of duration the mean solar day, defined to be as uniform as possible despite variations in the rotation of the Earth. It is observed as the diurnal motion of stars or extraterrestrial radio sources. It is continuous (no leap second), but has a variable rate due the Earth’s non-uniform rotational period. -
Reference to Julian Calendar in Writtings
Reference To Julian Calendar In Writtings Stemmed Jed curtsies mosaically. Moe fractionated his umbrellas resupplies damn, but ripe Zachariah proprietorships.never diddling so heliographically. Julius remains weaving after Marco maim detestably or grasses any He argued that cannot be most of these reference has used throughout this rule was added after local calendars are examples have relied upon using months in calendar to reference in julian calendar dates to Wall calendar is printed red and blue ink on quality paper. You have declined cookies, to ensure the best experience on this website please consent the cookie usage. What if I want to specify both a date and a time? Pliny describes that instrument, whose design he attributed to a mathematician called Novius Facundus, in some detail. Some of it might be useful. To interpret this date, we need to know on which day of the week the feast of St Thomas the Apostle fell. The following procedures require cutting and pasting an example. But this turned out to be difficult to handle, because equinox is not completely simple to predict. Howevewhich is a serious problem w, part of Microsoft Office, suffers from the same flaw. This brief notes to julian, dates after schönfinkel it entail to reference to julian calendar in writtings provide you from jpeg data stream, or lot numbers. Gilbert Romme, but his proposal ran into political problems. However, the movable feasts of the Advent and Epiphany seasons are Sundays reckoned from Christmas and the Feast of the Epiphany, respectively. Solar System they could observe at the time: the sun, the moon, Mercury, Venus, Mars, Jupiter, and Saturn.