eclipse

Documentation

Overview

Eclipse: Chapter 54, Eclipses.

Index

• Constants
• func Lunar(year float64) (eclipseType int, jmax, γ, ρ, σ, mag float64, ...)
• func Solar(year float64) (eclipseType int, central bool, jmax, γ, u, p, mag float64)

Constants

const (
	None         = iota
	Partial      // for solar eclipses
	Annular      // solar
	AnnularTotal // solar
	Penumbral    // for lunar eclipses
	Umbral       // lunar
	Total        // solar or lunar
)

Eclipse type identifiers returned from Solar and Lunar.

Functions

func Lunar

func Lunar(year float64) (eclipseType int, jmax, γ, ρ, σ, mag float64, sdTotal, sdPartial, sdPenumbral unit.Time)

Lunar computes quantities related to lunar eclipses.

Argument year is a decimal year specifying a date.

eclipseType will be None, Penumbral, Umbral, or Total. If None, none of the other return values may be meaningful.

jmax is the jde when the center of the eclipse shadow is closest to the Moon center, in a plane through the center of the Moon.

γ is the distance from the eclipse shadow center to the moon center at time jmax.

σ is the radius of the umbral cone in the plane of the Moon.

ρ is the radius of the penumbral cone.

mag is eclipse magnitude.

sd- return values are semidurations of the phases of the eclipse.

γ, σ, and ρ are in units of equatorial Earth radii.

func Solar

func Solar(year float64) (eclipseType int, central bool, jmax, γ, u, p, mag float64)

Solar computes quantities related to solar eclipses.

Argument year is a decimal year specifying a date.

eclipseType will be None, Partial, Annular, AnnularTotal, or Total. If None, none of the other return values may be meaningful.

central is true if the center of the eclipse shadow touches the Earth.

jmax is the jde when the center of the eclipse shadow is closest to the Earth center, in a plane through the center of the Earth.

γ is the distance from the eclipse shadow center to the Earth center at time jmax.

u is the radius of the Moon's umbral cone in the plane of the Earth.

p is the radius of the penumbral cone.

mag is eclipse magnitude for partial eclipses. It is not valid for other eclipse types.

γ, u, and p are in units of equatorial Earth radii.