Formula definition definition
Formula definitions are modern mathematical expressions of historical theoretical models, usually geometrically expressed, on which the different types of astronomical tables are based. They are used to suggest values when inputting tables content and to analyse mathematically table content.
Formula definition : Oblique ascension | Spherical astronomical: Oblique ascension
Table model definition
Explanation
The oblique ascension rho of a point R, on the ecliptic, rising on the horizon is the angular distance, VE, along the equator from the first point of Aries, V, to the east point E.
Formula
\(\rho\) oblique ascension
\(\epsilon\) obliquity
\(\lambda\) longitude of the point
\(\phi\) latitude of the observer
\(\rho=arctang(cos(\epsilon)\times tang(\lambda))-arcsin\{tan[arcsin(sin(\lambda)\times sin(\epsilon)]\times tan(\phi)\}\)
Parameters
| Obliquity of the ecliptic (ra) |
\(\epsilon(ra)\) 23 ; 51,20 |
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|---|---|---|---|---|
| Obliquity of the ecliptic (ad) |
\(\epsilon(ad)\) 23 ; 51,20 |
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| Geographical latitude |
\(\phi\) 49 ; |
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Modern definition
Same definition
Parameter estimation tip
obliquity(ra)=23;51,20° (Ptolemy)
obliquity(ad)=23;51,20° (Ptolemy)
latitude=49°
Graphical representation
