sun {moonsun}R Documentation

Equatorial coordinates for celectial objects (ephemerides)

Description

These functions compute equatorial coordinates of celestial objects at given day, their phase, position of the limb, distance from earth and the magnitude.

Usage

sun(jday = jd())
mercury(jday = jd())
venus(jday = jd())
mars(jday = jd())
jupiter(jday = jd())
saturn(jday = jd())
uranus(jday = jd())
neptune(jday = jd())
pluto(jday = jd())

Arguments

jday Julian Day number

Details

The algorithms used here are fairly simple and not with top-accuracy.

Sun is assumed to be always on ecliptic and no eccentric anomaly is considered. The accuracy should be within 10s of right ascension and few minutes of declination.

Planets position are calculated without solving the Kepler Equation and considering perturbations, so the accuracy is similar.

Value

An object of class "eqc, apos, data.frame", containing a row for each day, and following columns:

ra Right Ascension
d Declination
phase Percentage of bright area visible from Earth
angle Angle between the limb and north-south equatorial axis
dist Distance from Earth in AUs
size Size in arcsecs
mag Magnitude

Author(s)

Lukasz Komsta

Examples

options(latitude=51.25,longitude=22.5)  # Lublin, Poland
j=jd(length=30)                         # Next 30 days
sun(j)                                  # Equatorial position
as.hoc(sun(j),j)                        # Horizontal position at current time

[Package moonsun version 0.1 Index]