Information about New Moon
- This article is about the lunar phase; for other uses, see New Moon (disambiguation).
)
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.
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.
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.
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:
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.
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:
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 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: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 January 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:
- 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.
Religious use
- See also: Lunar calendar
Recently an attempt to dancing Muslims on a scientifically calculated worldwide calendar has been adopted by both the Fiqh Council of North America and European Council for Fatwa and Research. The new calculation requires that conjunction occur before sunset in Mecca, Saudi Arabia and that moon set on the following day must take place after sunset. These can be precisely calculated and therefore a unified calendar is imminent if it becomes adopted worldwide. [18][19]
The New Moon is the beginning of the clock in the Chinese calendar. Some Buddhist Chinese keep a vegetarian diet on the New Moon and Full Moon each month.
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 Israelites of Peru keep the New Moon as a Sabbath of rest. As an evangelical church they follow the Holy Bible's teachings believing that God sanctified the seventh day, Saturday as it is now more commonly known, as the Sabbath and the New Moons in addition to these. See Ezekiel 46:1,3. No work may be done from dusk until dusk, and the services run for 11 hours, although a large number spend 24 hours within the gates of the temples, sleeping and singing praises throughout the night.
The new moon is also an important event in Wicca.
The new moon is also important in astrology, as is the full moon.
References
1. ^ Jawad, Ala'a H. (Nov.1993). "How Long Is a Lunar Month?". Sky&Telescope: pp.76..77.
2. ^ 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.
3. ^ formula 47.1 in Jean Meeus (1991): Astronomical Algorithms (1st ed.) ISBN 0-943396-35-2
4. ^ M.Chapront-Touzé, J. Chapront (1988): "ELP2000-85: a semianalytical lunar ephemeris adequate for historical times". Astronomy & Astrophysics 190, 342..352
5. ^ 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
6. ^ 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).
7. ^ Derived Constant #14 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]
8. ^ 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.
9. ^ 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.
10. ^ 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)
11. ^ delay is − (−5.8681") / (60×60×360 "/circle) / (36525/29.530... lunations per Julian century)² × (29.530... days/lunation) days
12. ^ −5.8681" + 0.5×(−25.858 − −23.8946)
13. ^ F.R. Stephenson, Historical Eclipses and Earth's Rotation. Cambridge University Press 1997. ISBN 0-521-46194-4 . p.507, eq.14.3
14. ^ 31 s / (86400 s/d) / [ (36525 d/cy) / (29.530... d/lunation) ]²
15. ^ Stephenson 1997 op.cit. p.38 eq.2.8
16. ^ Stephenson 1997 op.cit. par.14.8
17. ^ from differerences of various earlier determinations of the tidal acceleration, see e.g. Stephenson 1997 op.cit. par.2.2.3
18. ^ Fiqh Council of North America Decision: "Fiqh Council Ramadan and Eid Announcement"
19. ^ Islamic Society of North America Decision:"Revised ISNA Ramadan and Eid Announcement"
2. ^ 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.
3. ^ formula 47.1 in Jean Meeus (1991): Astronomical Algorithms (1st ed.) ISBN 0-943396-35-2
4. ^ M.Chapront-Touzé, J. Chapront (1988): "ELP2000-85: a semianalytical lunar ephemeris adequate for historical times". Astronomy & Astrophysics 190, 342..352
5. ^ 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
6. ^ 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).
7. ^ Derived Constant #14 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]
8. ^ 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.
9. ^ 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.
10. ^ 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)
11. ^ delay is − (−5.8681") / (60×60×360 "/circle) / (36525/29.530... lunations per Julian century)² × (29.530... days/lunation) days
12. ^ −5.8681" + 0.5×(−25.858 − −23.8946)
13. ^ F.R. Stephenson, Historical Eclipses and Earth's Rotation. Cambridge University Press 1997. ISBN 0-521-46194-4 . p.507, eq.14.3
14. ^ 31 s / (86400 s/d) / [ (36525 d/cy) / (29.530... d/lunation) ]²
15. ^ Stephenson 1997 op.cit. p.38 eq.2.8
16. ^ Stephenson 1997 op.cit. par.14.8
17. ^ from differerences of various earlier determinations of the tidal acceleration, see e.g. Stephenson 1997 op.cit. par.2.2.3
18. ^ Fiqh Council of North America Decision: "Fiqh Council Ramadan and Eid Announcement"
19. ^ Islamic Society of North America Decision:"Revised ISNA Ramadan and Eid Announcement"
See also
- Black moon
- Blue moon
- Ecclesiastical new moon
- Full moon
- Half moon
- Dark moon
- Metonic cycle
- Lunar Cycle
External links
- Sacred Astronomy from Zaytuna institute
- CrescentWatch.org from Zaytuna Institute
- Moon sighting Committee World-wide of Khalid Shaukat
- Moon Sighting from Committee For Crescent Observation, Intl.
- Islamic Crescent Observation Project
- The Length of the Lunar Cycle (numerical integration analysis)
- Predicting the First Visibility of the Lunar Crescent
New Moon may refer to:
..... Click the link for more information.
- New moon, a lunar phase
- New Moon (magazine), a girls' magazine
- New Moon (novel), a 2005 young adult/horror/romance novel by Stephenie Meyer
- The New Moon
..... Click the link for more information.
Lunar phase refers to the appearance of the illuminated portion of the Moon as seen by an observer, usually on Earth. The lunar phases vary cyclically as the Moon orbits the Earth, according to the changing geometry of the Earth, Moon, and Sun.
..... Click the link for more information.
..... Click the link for more information.
Conjunction can refer to:
..... Click the link for more information.
- Astronomical conjunction, an astronomical phenomenon
- Astrological aspect, an aspect in horoscopic astrology
- Grammatical conjunction, a part of speech
- Logical conjunction, a mathematical operator
..... Click the link for more information.
crescent is generally the shape produced when a circular disk has a segment of another circle removed from its edge, so that what remains is a shape enclosed by two circular arcs of different diameters which intersect at two points (usually in such a manner that the enclosed shape
..... Click the link for more information.
..... Click the link for more information.
Moon
The Moon as seen by an observer on Earth
Orbital characteristics
Periapsis: 363,104 km
0.0024 AU
Apoapsis: 405,696 km
0.0027 AU
Semi-major axis: 384,399 km
0.
..... Click the link for more information.
The Moon as seen by an observer on Earth
Orbital characteristics
Periapsis: 363,104 km
0.0024 AU
Apoapsis: 405,696 km
0.0027 AU
Semi-major axis: 384,399 km
0.
..... Click the link for more information.
Conjunction is a term used in positional astronomy and astrology. It means that, as seen from some place (usually the Earth), two celestial bodies appear near one another in the sky. The event is also sometimes known as an appulse.
..... Click the link for more information.
..... Click the link for more information.
The Sun
Observation data
Mean distance
from Earth 1.4961011 m
(8.31 min at light speed)
Visual brightness (V) −26.74m [1]
Absolute magnitude 4.
..... Click the link for more information.
Observation data
Mean distance
from Earth 1.4961011 m
(8.31 min at light speed)
Visual brightness (V) −26.74m [1]
Absolute magnitude 4.
..... Click the link for more information.
horizon (Ancient Greek ὁ ὁρίζων, /ho horídzôn/, from ὁρίζειν, "to limit") is the line that separates earth from sky.
..... Click the link for more information.
..... Click the link for more information.
Sunset, also called sundown in some American English dialects, is the time at which the Sun disappears below the horizon in the west. It should not be confused with dusk, which is the point at which darkness falls, some time after the beginning of twilight when the Sun
..... Click the link for more information.
..... Click the link for more information.
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. Depending on how close the Moon passes to the line between Earth and Sun, dark moon may last between 1.5 to 3.5 days.
..... Click the link for more information.
..... Click the link for more information.
Ecliptic longitude (solar longitude or 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 the ecliptic coordinate system.
..... Click the link for more information.
..... Click the link for more information.
ECLiPSe is a constraint logic programming system that implements a programming language close to Prolog. ECLiPSe was developed until 1995 at the European Computer‐Industry Research Centre (ECRC) in Munich and then until 2005 at the Centre for Planning and Resource Control at
..... Click the link for more information.
..... Click the link for more information.
For the Egyptian hawk-god, see .
The month is a unit of time, used with calendars, which is approximately as extensive as some natural period related to the motion of the Moon.
..... Click the link for more information.
lunar calendar is a calendar in many cultures that is oriented at the moon phase.
This is normally done by having a month which corresponds to a lunation so that the day of month indicates the moon phase. If a calendar tracks the seasons, it is also a lunisolar calendar.
..... Click the link for more information.
This is normally done by having a month which corresponds to a lunation so that the day of month indicates the moon phase. If a calendar tracks the seasons, it is also a lunisolar calendar.
..... Click the link for more information.
Islamic calendar or Muslim calendar (Arabic: التقويم الهجري; at-taqwīm al-hijrī
..... Click the link for more information.
..... Click the link for more information.
lunisolar calendar is a calendar in many cultures whose date indicates both the moon phase and the time of the solar year. If the solar year is defined as a tropical year then a lunisolar calendar will give an indication of the season; if it is taken as a sidereal year then the
..... Click the link for more information.
..... Click the link for more information.
Hebrew calendar (Hebrew: הלוח העברי) or Jewish calendar is the calendar used by Jews for religious purposes.
..... Click the link for more information.
..... Click the link for more information.
Hindu calendar used in ancient times has undergone many changes in the process of regionalization, and today there are several regional Indian calendars, as well as an Indian national calendar. In Pakistan it is called 'desi' or native calendar.
..... Click the link for more information.
..... Click the link for more information.
Buddhist calendar is used on mainland Southeast Asia in the countries of Cambodia, Laos, Thailand, Myanmar (formerly Burma) and Sri Lanka in several related forms. It is a lunisolar calendar having months that are alternately 29 and 30 days, with an intercalated day and a 30-day
..... Click the link for more information.
..... Click the link for more information.
Chinese calendar is a lunisolar calendar, incorporating elements of a lunar calendar with those of a solar calendar. In China today, the Gregorian calendar is used for most day to day activities, but the Chinese calendar is still used for marking traditional Chinese holidays such
..... Click the link for more information.
..... Click the link for more information.
Conjunction can refer to:
..... Click the link for more information.
- Astronomical conjunction, an astronomical phenomenon
- Astrological aspect, an aspect in horoscopic astrology
- Grammatical conjunction, a part of speech
- Logical conjunction, a mathematical operator
..... Click the link for more information.
Terrestrial Time (TT) is the modern time standard for time on the surface of the Earth. It is the proper time experienced by a clock located on the geoid. In astronomy it is used as the time coordinate for apparent ephemerides for an Earthbound viewer.
..... Click the link for more information.
..... Click the link for more information.
An ephemeris (plural: ephemerides) (from the Greek word ephemeros = daily) is a table of values that gives the positions of astronomical objects in the sky at a given time or times. Different kinds are used for astronomy and astrology.
..... Click the link for more information.
..... Click the link for more information.
Universal Time (UT) is a timescale based on the rotation of the Earth. It is a modern continuation of Greenwich Mean Time (GMT), i.e., the mean solar time on the meridian of Greenwich, England, which is the conventional zero meridian for geographic longitude.
..... Click the link for more information.
..... Click the link for more information.
This article may contain original research or unverified claims.
..... Click the link for more information.
Please help Wikipedia by adding references. See the for details.
This article has been tagged since September 2007.
This article has been tagged since September 2007.
..... Click the link for more information.
Jean Meeus (born 1928) is a Belgian astronomer specializing in celestial mechanics. He is sometimes known as Jan Meeus. The asteroid 2213 Meeus is named after him.
..... Click the link for more information.
..... Click the link for more information.
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.
..... Click the link for more information.
..... Click the link for more information.
Light-time correction is a displacement in the apparent position of a celestial object from its true position (or geometric position) caused by the object's motion during the time it takes its light to reach an observer.
..... Click the link for more information.
..... Click the link for more information.
TT, Tt or tt may refer to:
..... Click the link for more information.
General
- Telegraphic transfer (or telex transfer), a method of transferring money
- TT scale (Table Top scale), a niche model railroading scale.
..... Click the link for more information.
UT (or U.T. or ut) may stand for or refer to
..... Click the link for more information.
- Ugly Things, a music magazine
- Unification Thought, the Unification Church philosophy.
- Universal Time, a standard time scale.
- Union Territory, an administration division in India.
- University Theater.
..... Click the link for more information.
This article is copied from an article on Wikipedia.org - the free encyclopedia created and edited by online user community. The text was not checked or edited by anyone on our staff. Although the vast majority of the wikipedia encyclopedia articles provide accurate and timely information please do not assume the accuracy of any particular article. This article is distributed under the terms of GNU Free Documentation License.
Herod_Archelaus
