mars

Documentation

Overview

Mars: Chapter 42, Ephemeris for Physical Observations of Mars.

Index

• func Physical(jde float64, earth, mars *pp.V87Planet) (DE, DS, ω, P, Q, d, q unit.Angle, k float64)

Examples

• Physical

Functions

func Physical

func Physical(jde float64, earth, mars *pp.V87Planet) (DE, DS, ω, P, Q, d, q unit.Angle, k float64)

Physical computes quantities for physical observations of Mars.

Results:

DE  planetocentric declination of the Earth.
DS  planetocentric declination of the Sun.
ω   Areographic longitude of the central meridian, as seen from Earth.
P   Geocentric position angle of Mars' northern rotation pole.
Q   Position angle of greatest defect of illumination.
d   Apparent diameter of Mars.
q   Greatest defect of illumination.
k   Illuminated fraction of the disk.

Example

package main

import (
	"fmt"

	"github.com/mooncaker816/learnmeeus/v3/mars"
	pp "github.com/mooncaker816/learnmeeus/v3/planetposition"
)

func main() {
	// Example 42.a, p. 291
	e, err := pp.LoadPlanet(pp.Earth)
	if err != nil {
		fmt.Println(err)
		return
	}
	m, err := pp.LoadPlanet(pp.Mars)
	if err != nil {
		fmt.Println(err)
		return
	}
	DE, DS, ω, P, Q, d, q, k := mars.Physical(2448935.500683, e, m)
	fmt.Printf("DE = %+.2f\n", DE.Deg())
	fmt.Printf("DS = %+.2f\n", DS.Deg())
	fmt.Printf("ω = %.2f\n", ω.Deg())
	fmt.Printf("P = %.2f\n", P.Deg())
	fmt.Printf("Q = %.2f\n", Q.Deg())
	fmt.Printf("d = %.2f\n", d.Sec()) // display as arc sec
	fmt.Printf("k = %.4f\n", k)
	fmt.Printf("q = %.2f\n", q.Sec()) // display as arc sec
}

Output:

DE = +12.44
DS = -2.76
ω = 111.55
P = 347.64
Q = 279.91
d = 10.75
k = 0.9012
q = 1.06