Formulas & tables/Physics/Astronomy

Astronomy

4 formulas · Physics

Synodic month (cycle of phases)
Tsyn=29.53059 dT_{syn} = 29.53059\ \text{d}
Sidereal month (relative to the stars)
Tsyd=27.32166 dT_{syd} = 27.32166\ \text{d}
Saros cycle
223 Tsyn=6585.32 d≈18yr 11d 8h223\,T_{syn} = 6585.32\ \text{d} \approx 18^{\text{yr}}\,11^{\text{d}}\,8^{\text{h}}
Angular size of a body
α=2arctan⁡ ⁣d2D≈dD\alpha = 2\arctan\!\frac{d}{2D} \approx \frac{d}{D}