The lunar phase depends on the Moon's position in orbit around Earth. This diagram looks down on the North pole; In astronomical terminology, the New Moon is the lunar phase that occurs when the Moon, in its monthly orbital motion around Earth, lies between Earth and the Sun, and is therefore in conjunction with the Sun as seen from Earth. At this time, the illuminated half of the Moon faces directly toward the Sun, and the dark or unilluminated portion of the Moon faces directly toward Earth, so that the Moon is invisible as seen from Earth. Diagram of lunar phases, created by Minesweeper and donated to Wikipedia. ...
Diagram of lunar phases, created by Minesweeper and donated to Wikipedia. ...
For other uses, see North Pole (disambiguation). ...
Lunar phase refers to the appearance of the illuminated portion of the Moon as seen by an observer, usually on Earth. ...
New Moon is often considered to occur at the time of the appearance of the first visible crescent of the Moon, after conjunction with the Sun. This takes place over the western horizon in a brief period between sunset and moonset, and therefore the precise time and even the date of the appearance of the New Moon by this definition will be influenced by the geographical location of the observer. The astronomical New Moon, sometimes known as the dark moon to avoid confusion, occurs by definition at the moment of conjunction in ecliptic longitude with the Sun, when the Moon is invisible from the Earth. This moment is unique and does not depend on location, and under certain circumstances it may be coincident with a solar eclipse. This article does not cite any references or sources. ...
This article is about Earths moon. ...
Sol redirects here. ...
Horizon. ...
A composite image showing the terminator dividing night from day, running across Europe and Africa. ...
Dark moon is the period when the Moon appears so close to the Sun in the sky that it cannot be seen even near sunset or sunrise. ...
Ecliptic longitude (celestial longitude) is one of the co-ordinates which can be used to define the location of an astronomical object on the celestial sphere in ecliptic coordinates. ...
This article is about astronomical eclipses. ...
The New Moon is the beginning of the month in lunar calendars such as the Muslim calendar, and in lunisolar calendars such as the Hebrew calendar, Hindu calendars, Buddhist calendar, and Chinese calendar. Look up Month in Wiktionary, the free dictionary. ...
A lunar calendar is a calendar oriented at the moon phase. ...
The Islamic calendar or Muslim calendar (Arabic: التقويم الهجري; at-taqwīm al-hijrī; Persian: تقویم هجري قمری ‎ taqwīm-e hejri-ye qamari; also called the Hijri calendar) is the calendar used to date events in many predominantly Muslim countries, and used by Muslims everywhere to determine the proper day on which to celebrate...
A lunisolar calendar is a calendar whose date indicates both the moon phase and the time of the solar year. ...
The Hebrew calendar (Hebrew: ‎) or Jewish calendar is the annual calendar used in Judaism. ...
A page from the Hindu calendar 1871-72. ...
The Buddhist calendar is used on mainland southeast Asia in the countries of Cambodia, Laos, Thailand, and Myanmar (formerly Burma) in several related forms. ...
The Chinese calendar is a lunisolar calendar, incorporating elements of a lunar calendar with those of a solar calendar. ...
Determining New Moons: an approximate formula
The time interval between New Moons - a lunation - is variable. The mean time between New Moons, the synodic month, is about 29.53... days. An approximate formula to compute the mean moments of New Moon (conjunction between Sun and Moon) for successive months is: In Egyptian mythology, Month is an alternate spelling for Menthu. ...
 where N is an integer, starting with 0 for the first New Moon in the year 2000, and that is incremented by 1 for each successive synodic month; and the result d is the number of days (and fractions) since 2000-01-01 00:00:00 reckoned in the time scale known as Terrestrial Time (TT) used in ephemerides. Terrestrial Time (TT) is the modern time standard for time on the surface of the Earth. ...
An ephemeris (plural: ephemerides) (from the Greek word ephemeros= daily) was, traditionally, a table providing the positions (given in a Cartesian coordinate system, or in right ascension and declination or, for astrologers, in longitude along the zodiacal ecliptic), of the Sun, the Moon, and the planets in the sky at...
To obtain this moment expressed in Universal Time (UT, world clock time), add the result of following approximate correction to the result d obtained above: Universal Time (UT) is a timescale based on the rotation of the Earth. ...
 days Periodic perturbations change the time of true conjunction from these mean values. For all New Moons between 1601 and 2401, the maximum difference is 0.592 days = 14h13m in either direction. The duration of a lunation (i.e. the time from New Moon to the next New Moon) varies in this period between 29.272 and 29.833 days, i.e. −0.259d = 6h12m shorter, or +0.302d = 7h15m longer than average [1][2]. This range is smaller than the difference between mean and true conjunction, because during one lunation the periodic terms cannot all change to their maximum opposite value.
See the article on the full moon cycle for a fairly simple method to compute the moment of New Moon more accurately. The full moon cycle is a cycle of about 14 lunations over which full moons vary in apparent size and age (time since new moon). ...
The long-term error of the formula is approximately: 1 cy² seconds in TT, and 11 cy² seconds in UT (cy is centuries since 2000; see section Explanation of the formulae for details.)
Explanation of the formula The moment of mean conjunction can easily be computed from an expression for the mean ecliptic longitude of the Moon minus the mean ecliptic longitude of the Sun (Delauney parameter D). Jean Meeus gave formulae to compute this in his popular Astronomical Formulae for Calculators based on the ephemerides of Brown and Newcomb (ca. 1900); and in his Astronomical Algorithms [3] based on the ELP2000-85 [4]. These are now outdated: Chapront et al. (2002) [5] published improved parameters. Also Meeus's formula uses a fractional variable to allow computation of the four main phases, and uses a second variable for the secular terms. For the convenience of the reader, the formula given above is based on Chapront's latest parameters and expressed with a single integer variable, and the following additional terms have been added: Jean Meeus (born 1928) is a Belgian astronomer specializing in celestial mechanics. ...
constant term:
- Like Meeus, apply the constant terms of the aberration of light for the Sun and light-time correction for the Moon[6] to obtain the apparent difference in ecliptic longitudes:
- Sun: +20.496" [7]
- Moon: −0.704" [8]
- Correction in conjunction: −0.000451 days. [9]
- For UT: at 1 Jan. 2000, ΔT (= TT − UT ) was +63.83 s [10]; hence the correction for the clock time UT = TT − ΔT of the conjunction is:
- −0.000739 days.
quadratic term: The aberration of light (also referred to as astronomical aberration or stellar aberration) is an astronomical phenomenon which produces an apparent motion of celestial objects. ...
Light-time correction is a slight angular shift in the apparent position of a celestial object, especially a planet, from its geometric position on the celestial sphere caused by the objects motion during the time it takes its light to reach Earth. ...
Delta T and delta-T are ASCII substitutes for the formal ΔT, which is Terrestrial Time minus Universal Time. ...
TT, Tt or tt may mean: Two races in motorcycle racing, TT meaning Tourist Trophy: Isle of Man TT Dutch TT The PlayStation 2 video game Tourist Trophy by Polyphony Digital Table Top (TT scale) in model railroading Teen Titans (comics or animated series) The Atari TT was a computer...
UT (or U.T. or ut) may stand for or refer to Abbreviations of the following universities: University of Tartu (Estonia) University of Tampa (USA) University of Tehran (Iran) Universiteit Twente (Netherlands) University of Tennessee (USA) University of Texas at Austin (USA) University of Tokyo (Japan) University of Toledo (USA...
- In ELP2000–85 (see Chapront et alii 1988), D has a quadratic term of −5.8681"T²; expressed in lunations N, this yields a correction of +87.403–12N2 [11] days to the time of conjunction. The term includes a tidal contribution of 0.5×(−23.8946 "/cy²). The most current estimate from Lunar Laser Ranging for the acceleration is (see Chapront et alii 2002): (−25.858 ±0.003) "/cy². Therefore the new quadratic term of D is = -6.8498"T² [12]. Indeed the polynomial provided by Chapront et alii (2002) provides the same value (their Table 4). This translates to a correction of +14.622−12N2 days to the time of conjunction; the quadratic term now is:
- +102.026−12N2 days.
- For UT: analysis of historical observations show that ΔT has a long-term increase of +31 s/cy² [13]. Converted to days and lunations [14], the correction from ET to UT becomes :
- −235−12N2 days.
The theoretical tidal contribution to ΔT is about +42 s/cy² [15]; the smaller observed value is thought to be mostly due to changes in the shape of the Earth [16]. Because the discrepancy is not fully explained, uncertainty of our prediction of UT (rotation angle of the Earth) may be as large as the difference between these values: 11 s/cy². The error in the position of the Moon itself is only maybe 0.5 "/cy² [17], or (because the apparent mean angular velocity of the Moon is about 0.5"/s), 1 s/cy² in the time of conjunction with the Sun. It has been suggested that Tidal friction be merged into this article or section. ...
Religious use - See also: Lunar calendar
The Islamic calendar has retained an observational definition of the New Moon, marking the new month when the first Crescent Moon is actually seen, and making it impossible to be certain in advance of when a specific month will begin (in particular, the exact date on which Ramadan will begin is not known in advance). In Saudi Arabia, if the weather is cloudy when the New Moon is expected, observers are sent up in airplanes. In Iran a special committee receives observations of every new moon to determine the beginning of each month. This committee uses one hundred groups of observers. A lunar calendar is a calendar oriented at the moon phase. ...
The Islamic calendar or Muslim calendar (Arabic: التقويم الهجري; at-taqwīm al-hijrī; Persian: تقویم هجري قمری ‎ taqwīm-e hejri-ye qamari; also called the Hijri calendar) is the calendar used to date events in many predominantly Muslim countries, and used by Muslims everywhere to determine the proper day on which to celebrate...
This article is about the Islamic calendar month by called Ramadan. ...
The New Moon is the beginning of the month in the Chinese calendar. Some Buddhist Chinese keep a vegetarian diet on the New Moon and Full Moon each month. Look up Month in Wiktionary, the free dictionary. ...
The New Moon signifies the start of every Jewish month, and is considered the most important date in the Hebrew calendar. The modern form of the calendar is a rule-based lunisolar calendar, akin to the Chinese calendar, measuring months defined in lunar cycles as well as years measured in solar cycles, and distinct from the purely lunar Islamic calendar and the almost entirely solar Gregorian calendar. The Hebrew calendar (Hebrew: ‎) or Jewish calendar is the annual calendar used in Judaism. ...
A lunisolar calendar is a calendar whose date indicates both the moon phase and the time of the solar year. ...
The Chinese calendar is a lunisolar calendar, incorporating elements of a lunar calendar with those of a solar calendar. ...
The Islamic calendar or Muslim calendar (Arabic: التقويم الهجري; at-taqwīm al-hijrī; Persian: تقویم هجري قمری ‎ taqwīm-e hejri-ye qamari; also called the Hijri calendar) is the calendar used to date events in many predominantly Muslim countries, and used by Muslims everywhere to determine the proper day on which to celebrate...
The Gregorian calendar is the most widely used calendar in the world. ...
The new moon is also an important event in Wicca. For other uses, see Wicca (disambiguation). ...
The new moon is also important in astrology, as is the full moon. Hand-coloured version of the anonymous Flammarion woodcut (1888). ...
Composite image of the Moon as taken by the Galileo spacecraft on 7 December 1992. ...
References - ^ Jawad, Ala'a H. (Nov.1993). "How Long Is a Lunar Month?". Sky&Telescope: pp.76..77.
- ^ Meeus, Jean (2002). The duration of the lunation, in More Mathematical Astronomy Morsels. Willmann-Bell, Richmond VA USA, 19..31. ISBN 0-943396-74-3.
- ^ formula 47.1 in Jean Meeus (1991): Astronomical Algorithms (1st ed.) ISBN 0-943396-35-2
- ^ M.Chapront-Touzé, J.Chapront (1988): "ELP2000-85: a semianalytical lunar ephemeris adequate for historical times". Astronomy & Astrophysics 190, 342..352
- ^ J.Chapront, M.Chapront-Touzé, G.Francou (2002): "A new determination of lunar orbital parameters, precession constant, and tidal acceleration from LLR measurements". Astronomy & Astrophysics 387, 700–709
- ^ Annual aberration is the ratio of Earth's orbital velocity (around 30 km/s) to the speed of light (about 300,000 km/s), which shifts the Sun's apparent position relative to the celestial sphere toward the west by about 1/10,000 radian. Light-time correction for the Moon is the distance it moves during the time it takes its light to reach Earth divided by the Earth-Moon distance, yielding an angle in radians by which its apparent position lags behind its computed geometric position. Light-time correction for the Sun is negligible because it is almost motionless during 8.3 minutes relative to the barycenter (center-of-mass) of the solar system. The aberration of light for the Moon is also negligible (the center of the Earth moves too slowly around the Earth-Moon barycenter (0.002 km/s); and the so-called diurnal aberration, caused by the motion of an observer on the surface of the rotating Earth (0.5 km/s at the equator) can be negelected. Although aberration and light-time are often combined as planetary aberration, Meeus separated them (op.cit. p.210).
- ^ Derived Constant #14 from from the IAU (1976) System of Astronomical Constants (proceedings of IAU Sixteenth General Assembly (1976): Transactions of the IAU XVIB p.58 (1977)); or any astronomical almanac; or e.g. [1]
- ^ formula in: G.M.Clemence, J.G.Porter, D.H.Sadler (1952): "Aberration in the lunar ephemeris", Astronomical Journal 57(5) (#1198) pp.46..47 [2]; but computed with the conventional value of 384400 km for the mean distance which gives a different rounding in the last digit.
- ^ Apparent mean solar longitude is −20.496" from mean geometric longitude; apparent mean lunar longitude −0.704" from mean geometric longitude; correction to D = Moon − Sun is −0.704" + 20.496" = +19.792" that the apparent Moon is ahead of the apparent Sun; divided by 360×3600"/circle is 1.527..−5 part of a circle; multiplied by 29.53... days for the Moon to travel a full circle with respect to the Sun is 0.000451 days that the apparent Moon reaches the apparent Sun ahead of time.
- ^ see e.g. [3]; the IERS is the official source for these numbers; they provide TAI−UTC here and UT1−UTC here; ΔT = 32.184s + (TAI−UTC) − (UT1−UTC)
- ^ delay is − (−5.8681") / (60×60×360 "/circle) / (36525/29.530... lunations per Julian century)² × (29.530... days/lunation) days
- ^ −5.8681" + 0.5×(−25.858 − −23.8946)
- ^ F.R. Stephenson, Historical Eclipses and Earth's Rotation. Cambridge University Press 1997. ISBN 0-521-46194-4 . p.507, eq.14.3
- ^ 31 s / (86400 s/d) / [ (36525 d/cy) / (29.530... d/lunation) ]²
- ^ Stephenson 1997 op.cit. p.38 eq.2.8
- ^ Stephenson 1997 op.cit. par.14.8
- ^ from differerences of various earlier determinations of the tidal acceleration, see e.g. Stephenson 1997 op.cit. par.2.2.3
In physics, the center of mass of a system of particles is a specific point at which, for many purposes, the systems mass behaves as if it was concentrated. ...
The International Earth Rotation Service (IERS) is the body responsible for maintaining global time and reference frame standards, notably through its Earth Orientation Paramater (EOP) and International Celestial Reference System (ICRS) groups. ...
The Tai languages are a subgroup of the Tai Kadai language family. ...
...
Universal Time (UT) is a timescale based on the rotation of the Earth. ...
In astronomy, a Julian year is a unit of time defined as exactly 365. ...
See also In astronomy, the term black moon is neither well known nor frequently used. ...
The term blue moon has at least four related meanings. ...
An ecclesiastical new moon is the first day of a schematic lunar month in a computus. ...
Composite image of the Moon as taken by the Galileo spacecraft on 7 December 1992. ...
see the Half Moon disambiguation page for other meanings A half moon is the phase of the moon midway between a full moon and a new moon. ...
Dark moon is the period when the Moon appears so close to the Sun in the sky that it cannot be seen even near sunset or sunrise. ...
The Metonic cycle or Enneadecaeteris in astronomy and calendar studies is a particular approximate common multiple of the year (specifically, the seasonal tropical year) and the synodic month. ...
In astronomy, a phase of the Moon is any of the aspects or appearances presented by the Moon as seen from Earth, determined by the portion of the Moon that is visibly illuminated by the Sun. ...
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