3 articles for "Obliquity"

**Obliquity**[Astro*Index]

The angle between the *Ecliptic* and the *Celestial Equator* circles. Also, the dihedral angle between the planes of the Ecliptic and the Celestial Equator. Note that Tables of Houses are computed using a fixed value for the Obliquity; hence, such tables are not valid for all historical periods. Thus, values obtained from computer programs may differ slightly from those obtained by interpoplation from such tables.

The Mean Obliquity may be computed from the following formula:

Mean Obliquity = 23°27'08.26" -46.845T

-0.0059"T2 - 0.00181"T3

where T is measured in Julian centuries of 36525 ephemeris days from the epoch:

G1900 JAN 00.5 ET = JD 2415020.0

True Obliquity is obtained by adding the Nutation in Obliquity to the Mean Obliquity.

See also: ♦ Ephemeris Time ♦ Nutation ♦ Ecliptic ♦ Celestial Equator

**Obliquity**[Munkasey M.]

The angle between the Ecliptic and the Celestial Equator.This angle is very important to This angle is very important to astrologers because almost all house systems use this angle in their derivation. Therefore as the angle changes with time, which it does, the values on the house cusps change too.

See also: ♦ Ephemeris Time ♦ Nutation ♦ Ecliptic ♦ Celestial Equator

**Obliquity of the Ecilptic**[Munkasey M.]

**(1)** The mathematical value computed when 90 degrees is added to the RAMC.

**(2)** See also: "Epoch"; and "Eccentric Anomoly".

See also: ♦ Epoch ♦ Nutation ♦ Eccentric Anomoly ♦ Obliquity

Astro*Index Copyright © 1997 Michael Erlewine

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