Function meanObliquity

meanObliquity(T: number): number
Calculate the mean obliquity of the ecliptic

Uses the Laskar 1986 formula, which is accurate for ±10,000 years around J2000. This is a simplified version of the full IAU formula, sufficient for astrological calculations.

Formula: ε₀ = 23.43929111° - 0.013004166°*T - 1.6388889×10⁻⁷°*T² + 5.0361111×10⁻⁷°*T³

where T = Julian Centuries from J2000.0 = (JD - 2451545.0) / 36525
Parameters
- T: number
  Julian Centuries from J2000.0 epoch
Returns number
Mean obliquity of ecliptic in degrees
See
"Astronomical Algorithms" by Jean Meeus, Chapter 22, page 147
Example
Calculate obliquity at J2000.0 epoch (T = 0):
```
const obliquity = meanObliquity(0);
console.log(obliquity);  // ~23.439° (23°26'21")
```
Example
Calculate obliquity one century after J2000:
```
const obliquity = meanObliquity(1.0);
console.log(obliquity);  // ~23.427° (slightly decreased)
```
Example
With Julian Centuries from time module:
```
import { toJulianCenturies } from '../time/julian-centuries.js';

const T = toJulianCenturies(2460665.0);  // Some Julian Date
const obliquity = meanObliquity(T);
```
- Defined in houses/obliquity.ts:60