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	Julian year (astronomy) - Wikipedia, the free encyclopedia
		Julian years are used primarily for convenience in ephemeris work where stating a number of days would be unwieldy (for instance, it is easier to express the orbital period of Pluto as 248 Julian years rather than 90,590 days).
		The "year" used in the definition of light year is a Julian year (note that a light year is a unit of distance, not time).
		Julian years are not to be confused with the Julian day (or Julian date), which is also used in astronomy.
	en.wikipedia.org /wiki/Julian_year_(astronomy) (690 words)

	Year - Wikipedia, the free encyclopedia
		A seasonal year is the time between successive recurrences of a seasonal event such as the flooding of a river, the migration of a species of bird, the flowering of a species of plant, the first frost, or the first scheduled game of a certain sport.
		A tropical year is the time for the Earth to complete one revolution with respect to the framework provided by the intersection of the ecliptic (the plane of the orbit of the Earth) and the plane of the equator (the plane perpendicular to the rotation axis of the Earth).
		The draconitic year, eclipse year or ecliptic year is the time for the Sun (as seen from the Earth) to complete one revolution with respect to the same lunar node (a point where the Moon's orbit intersects the ecliptic).
	en.wikipedia.org /wiki/Year (1812 words)

	Year
		A year is the term for any period of time that is derived from the period of the orbit of the Earth around the Sun.
		The actual duration varies from year to year because the motion of the Earth is influenced by the gravity of the Moon and other planets.
		tropical year: the period for the Earth to complete one revolution with respect to the framework provided by the intersection of the ecliptic (the plane of the orbit of the Earth) and the plane of the equator (the plane perpendicular to the rotation axis of the Earth).
	www.ebroadcast.com.au /lookup/encyclopedia/ye/Year.html (612 words)

	Sidereal year - Wikipedia, the free encyclopedia
		The sidereal year is the time for the Sun to return to the same position in respect to the stars of the celestial sphere.
		The sidereal year is the orbital period of Earth.
		Up to the time of Hipparchus, the years measured by the stars were thought to be exactly as long as the tropical years.
	en.wikipedia.org /wiki/Sidereal_year (326 words)

	Light year
		More specifically, a light year is defined as the distance that a photon would travel, in free space and infinitely far away from any gravitational or magnetic fields, in one Julian year (365.25 days of 86400 seconds each).
		The light year is used to measure large distances, like the distance from the solar system to a nearby star.
		In astronomy, the parsec is nowadays the preferred unit for large distances; one parsec equals 3.26 light-years.
	www.ebroadcast.com.au /lookup/encyclopedia/li/Light-years.html (289 words)

	Julian date
		The Julian Day (JD) or Julian Day Number is the time that has elapsed since noon January 1, 4713 BC[?] (according to the proleptic Julian calendar; or November 24, 4714 BC according to the proleptic Gregorian calendar), expressed in days and fractions of a day.
		In his book Outlines of Astronomy, published in 1849, the astronomer John Herschel recommended that a version of Scaliger's scheme should be used to make a standard system of time for astronomy.
		Julian dates are typically used by astronomers to calculate astronomical events, and eliminate the complications resulting from using standard calendar periods.
	www.ebroadcast.com.au /lookup/encyclopedia/ju/Julian_date.html (657 words)

	Wikinfo \| Year
		eclipse or ecliptic year: the period for the Sun (as seen from the Earth) to complete one revolution with respect to a node of the Moon's orbit (the points where the Moon's orbit intersects the ecliptic).
		The gaussian year lasts 365.2568983 days, and is derived from the Gaussian gravitational constant that is expressed in units of the solar system.
		Besselian year: this is a tropical year that starts when the mean Sun reaches the ecliptic longitude of 280°.
	www.wikinfo.org /wiki.php?title=Years (782 words)

	* Julian Year - (Astronomy): Definition
		This period served as the basis for the Julian calendar.
		Worse, the reckoned Moon that was used to compute Easter was fixed to the Julian year by a 19-year cycle.
		The calendric system employing the rules of the Julian calendar, but extended and applied to dates preceding the introduction of the Julian calendar itself.
	en.mimi.hu /astronomy/julian_year.html (131 words)

	CalendarHome.com - Year - Calendar Encyclopedia
		Rather than being based on numerical rules, the beginning of the Persian year is marked by the exact moment of the vernal equinox, as precisely determined by astronomical observations from Tehran.
		No astronomical year has an integer number of days or months, so any calendar that follows an astronomical year must have a system of intercalation such as leap years.
		It differs from the sidereal year for stars north or south of the ecliptic because of the significant angle (23.5°) between Earth's celestial equator and the ecliptic.
	encyclopedia.calendarhome.com /Year.htm (1667 words)

	Julian day - Indopedia, the Indological knowledgebase (Site not responding. Last check: 2007-10-13)
		The Julian day or Julian day number (JDN) is the number of days that have elapsed since noon Monday, January 1, 4713 BC (according to the proleptic Julian calendar; or November 24, 4714 BC, according to the proleptic Gregorian calendar).
		The Heliocentric Julian Day (HJD) is the same as the Julian day, but adjusted to the frame of reference of the sun, and thus can differ from the Julian day by as much as 8.3 minutes, that being the time it takes light to reach Earth from the Sun.
		Julian days are typically used by astronomers to date astronomical events, thus eliminating the complications resulting from using standard calendar periods like eras, years, months, or weeks.
	www.indopedia.org /AJD.html (1249 words)

	Astronomy Answers: From the Astronomical Dictionary
		The length of the tropical year depends on the ecliptical position that the year is tied to, and on whether the true Sun or the mean Sun (that ignores small disturbances) is meant.
		Sometimes, tropical year is used as the name for what I call the ascending-equinox year above (the year defined by the ascending equinox, which is the vernal equinox).
		Sometimes, tropical year is used for the average over all positions along the ecliptic (the average over all seasons).
	www.astro.uu.nl /~strous/cgi-bin/glossary.cgi?l=en&o=year (576 words)

	year concept from the Astronomy knowledge base (Site not responding. Last check: 2007-10-13)
		The beginning of a Besselian year, traditionally used as as standard epoch, is denoted by the suffix ".0".
		Julian year (3 facts) - A period served as the basis for the Julian calendar.
		sidereal year (2 facts) - A period of time based on the revolution of the Earth around the Sun, where a year is defined as the mean period of revolution with respect to the background stars.
	www.site.uottawa.ca:4321 /astronomy/year.html (312 words)

	Light-year
		A light-year, abbreviated ly, is the distance light travels in one year: roughly 9.46 trillion kilometers (or about 5.88 trillion miles).
		More specifically, a light-year is defined as the distance that a photon would travel, in free space and infinitely far away from any gravitational or magnetic fields, in one Julian year (365.25 days of 86400 seconds each).
		In astronomy, the perferred unit of measure for such distances is the parsec which defined as the distance at which an object will generate one arcsecond of parallax when the observing object moved one astronomical unit.
	www.guajara.com /wiki/en/wikipedia/l/li/light_year_1.html (446 words)

	Light Year Encyclopedia Articles @ LaunchBase.net (Launch Base) (Site not responding. Last check: 2007-10-13)
		In astronomy, the preferred unit of measurement for such distances is the parsec which is defined as the distance at which an object will generate one arcsecond of parallax when the observing object moved one astronomical unit perpendicular to the line of sight to the observer.
		The Triangulum Galaxy (M33), at a bit under 2.6 million light years away, is the most distant object visible to the naked eye.
		The particle horizon (observable part) of the universe has a radius of about 46 billion light years, but light from the edge of the observable universe was emitted only 13.7 billion years ago (the age of the universe).
	www.launchbase.net /encyclopedia/Light_year (513 words)

	AllRefer.com - Julian Day calendar (Astronomy, General) - Encyclopedia
		Julian Day calendar, system of astronomical dating that allows the difference between two dates to be calculated more easily than conventional civil calendars with their uneven months.
		The Julian Day number for Dec. 31, 1999, is 2,451,544; for Jan. 1, 2000, is 2,451,545; for Jan. 2, 2000, is 2,451,546; and so on.
		The Julian Day is from noon, universal time, on the given date to noon of the following date.
	reference.allrefer.com /encyclopedia/J/JulianDa.html (273 words)

	Astronomy Portal @ AstronomyInArt.com (Astronomy in Art) (Site not responding. Last check: 2007-10-13)
		Astronomy (Greek: αστρονομία = άστρον + νόμος, astronomia = astron + nomos, literally, "law of the stars") is the science of celestial objects (e.g., stars, planets, comets, and galaxies) and phenomena that originate outside the Earth's atmosphere (e.g., auroras and cosmic background radiation).
		A traditional division of astronomy is given by the region of the electromagnetic spectrum observed.
		Modern astronomy has also discovered many exotic objects such as quasars, pulsars, blazars and radio galaxies, and has used these observations to develop physical theories which describe some of these objects in terms of equally exotic objects such as fl holes and neutron stars.
	www.astronomyinart.com (3839 words)

	Calendars - Numericana
		The Julian day number associated with the solar day is the number assigned to a day in a continuous count of days beginning with the Julian day number 0 assigned to the day starting at Greenwich mean noon on 1 January 4713 BC, Julian proleptic calendar -4712.
		The pattern of weekdays and leap years repeats with a 28 year cycle in the Julian Calendar (it's 400 years with the modern Gregorian calendar).
		(Gregorian year Y) C is -4 from 1583 to 1699, -5 from 1700 to 1899, -6 from 1900 to 2199, -7 from 2200 to 2299.
	home.att.net /~numericana/answer/calendar.htm (8129 words)

	NationMaster - Encyclopedia: Earth
		In astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified.
		In astronomy, a Julian year is a unit of time defined as exactly 365.
		In astronomy, declination (dec) is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle.
	www.nationmaster.com /encyclopedia/Earth (2155 words)

	Julian day number and Julian period
		If every year is described by its place in these lunar and solar cycles (e.g., “this year is the 23rd year of the solar cycle and the 7th year of the lunar cycle”), 532 years can pass before two years will have the same description (19 × 28 = 532).
		The Julian Day number is not a measure of time; it is actually a unit of count, a count of days.
		It is often said that Scaliger named the Julian period after his father, but at the end of the introductory section to Book V of De Emendatione Temporum he explicitly states that he named his period after the Julian year.
	www.sizes.com /time/dayJulianr.htm (988 words)

	The Astrophysics Spectator: Table-Basic Measures in Astronomy (Site not responding. Last check: 2007-10-13)
		Over the course of a year, a 1 parsec star moves by 2 arc-seconds across the sky, because the baseline is the diameter of Earth's orbit, which is 2 AU.
		The second value for the length of the parsec is expressed in Julian light years (the distance light travels in a Julian year of 365.25 days).
		The tropical year is the year that the Gregorian calendar is based on, and it is measured relative to the first point of Aries.
	www.astrophysicsspectator.com /tables/BasicValues.html (1001 words)

	The Origin of Julian Days
		Most astronomy texts explain that it is based on the number of days that have elapsed since noon universal time (UT), 1 January 4713 BCE (before current era, or B.C.); for example, 1 January 1996 CE (current era, or A.D.) is equivalent to Julian day 2,450,084.
		Contemporaries dubbed it the "year of confusion", although its purpose was to end confusion.
		In 19 years of exactly 365.25 days each (the Julian, or solar year), there are 235 lunar cycles, with seven of these years having a 13th, or embolistic, month.
	www.magma.ca /~scarlisl/DRACO/julian_d.html (1426 words)

	Glossary of astronomical terms
		The recent change to Julian year usage in dynamical astronomy (and the J2000.0 equinox) took effect in solar-system ephemerides of the Minor Planet Center and Central Bureau for Astronomical Telegrams on Jan. 1, 1992.
		When this dynamical, artificial "Julian year" is employed, a letter "J" prefixes the year.
		In astronomy, the measurement of the light emitting from astronomical objects, generally in the visible or infrared bands, in which a specific or general wavelength band is normally specified.
	cfa-www.harvard.edu /icq/ICQGlossary.html (3501 words)

	Julian year - Facts, Information, and Encyclopedia Reference article (Site not responding. Last check: 2007-10-13)
		The Julian year (astronomy) is time interval of exactly 365.25 days, used in astronomy.
		The Julian year (calendar) is a year in the Julian calendar which has started on different days, at different times, in different countries and is equal to either 365 or 366 days, or 365.25 days on average.
		If an article link referred you to this title, you might want to go back and fix it to point directly to the intended page.
	www.startsurfing.com /encyclopedia/j/u/l/Julian_year.html (101 words)

	Curious About Astronomy: Why are most months 30 or 31 days long?
		However, the Julian year still differs from the true year and by 1582, the error had accumulated to 10 days.
		In addition, a modification was made that century years that were not divisible by 400 would not be considered as leap years.
		This made the year sufficiently close to the actual year and this calender is called the Gregorian calender.
	curious.astro.cornell.edu /question.php?number=187 (411 words)

	Astronomical Astronomy Glossary Dictionary Terminology meanings
		Julian date (JD) The interval of time in days (and fraction of a day) since Greenwich noon on Jan. 1, 4713 BC.
		Julian year Exactly 365.25 days, in which a century (100 years) is exactly 36525 days and in which 1900.0 corresponds exactly to 1900 January 0.5 (from the Julian-date system, which is half a day different from civil time or UT).
		Photometry In astronomy, the measurement of the light emitting from astronomical objects, generally in the visible or infrared bands, in which a specific or general wavelength band is normally specified.
	www.aoe.com.au /astronomical_glossary.html (6593 words)

	YourArt.com >> Encyclopedia >> Year (Site not responding. Last check: 2007-10-13)
		353, 354 or 355 days — the lengths of common years in some lunisolar calendars
		354.37 days — 12 lunar months; the average length of a year in lunar calendars
		365.25 days — the average length of a year in the Julian calendar
	www.yourart.com /research/encyclopedia.cgi?subject=/Year (1793 words)

	Vedic Astronomy
		The plot shows that during the period 3300BC to 700 BC, (Julian year corresponds to zero at 4712 BC- an imaginary date- Our range corresponds to 1412 Julian year to 4012 Julian Year) nearly 672 pairs of eclipses occurred on earth, which in principle may have been visible at Kuruxethra.
		On Julian August 11 afternoon, a solar eclipse begins at 6:54 before sunset and it is still on going at sunset at 7:14.
		Fourteen days later (On Julian July 11,2559) in the morning at sunrise the solar eclipse is already occurring and is almost over suggesting it started on the 13th day after the previous lunar eclipse.
	www.vedicastronomy.net /mb_kuruxethra.htm (2221 words)

	* Julian Date - (Astronomy): Definition
		See also: Year, Julian Calendar, Period, Calendar, Time
		The system, defined as the Julian date minus 2,400,000.5, is also occasionally used by astronomers, but not so frequently in recent years.
		The scale on the bottom is the "Julian Date" of 2440000 plus the number that appears, where the Julian Date is the number of days since January 1, 4713 BC of the Julian Calendar and is commonly used for variable phenomena in astronomy.
	en.mimi.hu /astronomy/julian_date.html (192 words)

	How far is a light-year? In miles and kilometers. - Answerbag
		A light year is a unit of distance (not time!) equal to the speed of light in a vacuum times the duration of one Julian year--in other words, how far light could travel in a vacuum in a year, assuming no influence by gravitational or magnetic fields.
		For what it's worth, a light year is also about 63,241.077 astronomical units, which are the defined as the average distance between the earth and the sun.
		The year in "light year" is a "Julian year" which is always exactly 365.25 days.
	www.answerbag.com /q_view.php/2245 (678 words)

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