Definitions for evection
evec·tion

WiktionaryRate this definition:0.0 / 0 votes

1. evectionnoun

   Modification of the lunar orbit due to the gravitational effects of the Sun.

WikipediaRate this definition:0.0 / 0 votes

1. Evection

   In astronomy, evection (Latin for "carrying away") is the largest inequality produced by the action of the Sun in the monthly revolution of the Moon around the Earth. The evection, formerly called the moon's second anomaly, was approximately known in ancient times, and its discovery is attributed to Ptolemy. The current name itself dates much more recently, from the 17th century: it was coined by Bullialdus in connection with his own theory of the Moon's motion.Evection causes the Moon's ecliptic longitude to vary by approximately ± 1.274° (degrees), with a period of about 31.8 days. The evection in longitude is given by the expression + 4586.45 ″ sin ⁡ ( 2 D − ℓ ) {\displaystyle +4586.45''\sin(2D-\ell )} , where D {\displaystyle D} is the mean angular distance of the Moon from the Sun (its elongation), and ℓ {\displaystyle \ell } is the mean angular distance of the Moon from its perigee (mean anomaly).It arises from an approximately six-monthly periodic variation of the eccentricity of the Moon's orbit and a libration of similar period in the position of the Moon's perigee, caused by the action of the Sun.The evection opposes the Moon's equation of the center at the new and full moons, and augments the equation of the center at the Moon's quarters. This can be seen from the combination of the principal term of the equation of the center with the evection: + 22639.55 ″ sin ⁡ ( ℓ ) + 4586.45 ″ sin ⁡ ( 2 D − ℓ ) . {\displaystyle +22639.55''\sin(\ell )+4586.45''\sin(2D-\ell ).} At new and full moons, D=0° or 180°, 2D is effectively zero in either case, and the combined expression reduces to + ( 22639.55 − 4586.45 ) ″ sin ⁡ ( ℓ ) . {\displaystyle +(22639.55-4586.45)''\sin(\ell ).} At the quarters, D=90° or 270°, 2D is effectively 180° in either case, changing the sign of the expression for the evection, so that the combined expression then reduces to + ( 22639.55 + 4586.45 ) ″ sin ⁡ ( ℓ ) {\displaystyle +(22639.55+4586.45)''\sin(\ell )} .

Webster DictionaryRate this definition:0.0 / 0 votes

1. Evection

   the act of carrying up or away; exaltation

2. Evection

   an inequality of the moon's motion is its orbit to the attraction of the sun, by which the equation of the center is diminished at the syzygies, and increased at the quadratures by about 1¡ 20'.

3. Evection

   the libration of the moon

4. Etymology: [L. evectio a going up, fr. evehere to carry out; e out + vehere to carry: cf. F vection.]

WikidataRate this definition:1.0 / 1 vote

1. Evection

   Evection, in astronomy, is the largest inequality produced by the action of the Sun in the monthly revolution of the Moon around the Earth. The evection, formerly called the moon's second anomaly, was approximately known in ancient times, and its discovery is attributed to Ptolemy. Evection causes the Moon's ecliptic longitude to vary by approximately ± 1.274°, with a period of about 31.8 days. The evection in longitude is given by the expression, where is the elongation, i.e. mean angular distance of the Moon from the Sun, and is the moon's mean anomaly, i.e. mean angular distance of the moon from its perigee. It can be considered as arising from an approximately 6-monthly periodic variation of the eccentricity of the Moon's orbit and a libration of similar period in the position of the Moon's perigee, caused by the action of the Sun. The evection can be considered as opposing the Moon's equation of the center at the new and full moons, and augmenting the equation of the center at the Moon's quarters. This can be seen from the combination of the principal term of the equation of the center with the evection: .

Chambers 20th Century DictionaryRate this definition:0.0 / 0 votes

1. Evection

   e-vek′shun, n. (astron.) a lunar inequality resulting from the combined effect of the irregularity of the motion of the perigee, and alternate increase and decrease of the eccentricity of the moon's orbit. [L. evection-em—e, out, vehĕre, vectum, to carry.]

Dictionary of Nautical TermsRate this definition:0.0 / 0 votes

1. evection

   A term for the libration of the moon, or that apparent oscillatory inequality in her motion, caused by a change in the excentricity of her orbit, whereby her mean longitude is sometimes increased or diminished to the amount of 1° 20′, whereby we sometimes see a little further round one side than at others.

Anagrams for evection »

1. civetone

How to pronounce evection?

1. Alex

   US English

   David

   US English

   Mark

   US English

   Daniel

   British

   Libby

   British

   Mia

   British

   Karen

   Australian

   Hayley

   Australian

   Natasha

   Australian

   Veena

   Indian

   Priya

   Indian

   Neerja

   Indian

   Zira

   US English

   Oliver

   British

   Wendy

   British

   Fred

   US English

   Tessa

   South African

How to say evection in sign language?

Numerology

1. Chaldean Numerology

   The numerical value of evection in Chaldean Numerology is: 9

2. Pythagorean Numerology

   The numerical value of evection in Pythagorean Numerology is: 3

References

1. ^ Wiktionary
   https://en.wiktionary.org/wiki/Evection
2. ^ Wikipedia
   https://en.wikipedia.org/wiki/Evection
3. ^ Webster Dictionary
   https://www.merriam-webster.com/dictionary/evection
4. ^ Wikidata
   https://www.wikidata.org/w/index.php?search=evection
5. ^ Chambers 20th Century Dictionary
   https://www.gutenberg.org/files/37683/37683-h/37683-h.htm#:~:text=evection
6. ^ Dictionary of Nautical Terms
   https://www.gutenberg.org/cache/epub/26000/pg26000-images.html#:~:text=evection