moonsun (version 0.1.3)

track: Plot track of planets

Description

To plot tracts of planets during to dates.

Usage

track(ephem, mag = 7, edge = 0.2, cex.star = 1,xlab = "Right Ascension", ylab = expression(paste("Declination", degree)), col.track = "red",  interval.lab = 15, lwd.track = 2, grid = TRUE, bright.lab = TRUE, bright, starcat,...)

Arguments

ephem

Equatorial coordinates of celestial objects as generated. see planet for more information.

mag

Magnitude of stars to be plot on the background.

edge

Numeric, the edge extention of the plots from each side of the ploting margin.

cex.star

Numeric, indicating the point size of the stars to be ploted on the background.

xlab

label for the x axis.

ylab

label for the y axis.

col.track

color of the planet's track .

interval.lab

Time interval for the label.

lwd.track

Line width of the planet's track.

grid

Whether the grid of coordinate's should be drawn.

bright.lab

Whether to draw the labels of bright stars on the plot.

bright

Data frame for bright stars

starcat

Star catalogue used in plotting.

...

Other specified methods to draw the plot.

Value

NULL

Details

User may employ this function when she/he wants to see the tracks of certain planet during time 1 to time 2. The input data should be generated by planet,or planet related functions such as mercury,mars,saturn. User may define her/his own celestral objects and plot the tracks using this function.

References

http://www.clearskyinstitute.com/xephem/

http://www.alcyone.de/

Examples

# Beijing
options(longitude = 116.433, latitude = 39.874)

### plot the background of sky chart
data(bright)
data(starcat)

ephem.mercury <- mercury(jd(2010,1,1,length = 365))
track(ephem.mercury, mag = 4, interval.lab = 30, bright.lab = TRUE, 
	starcat = starcat, bright = bright)

ephem.mercury <- mercury(jd(2010,7,30,length = 60))
track(ephem.mercury, mag = 7, interval.lab = 10, cex.star = 2, starcat = starcat, bright = bright)

ephem.venus <- venus(jd(2011,4,30,length = 100))
track(ephem.venus, col.track = "blue", lwd = 3, mag = 5, starcat = starcat, bright = bright)

ephem.mars <- mars(jd(2010,8,30,length = 100))
track(ephem.mars, cex.star = 1.5, grid = FALSE, starcat = starcat, bright = bright)

ephem.jupiter <- jupiter(jd(2010,9,22,length = 100))
track(ephem.jupiter, cex.star = 1.5, col.track = "black" , starcat = starcat, bright = bright)

ephem.saturn <- saturn(jd(2011,9,22,length = 100))
track(ephem.saturn, starcat = starcat, bright = bright)

ephem.uranus <- uranus(jd(2008,8,1,length = 100))
track(ephem.uranus, starcat = starcat, bright = bright)