star_visibility: Star visibility information when certain star sets or rises...

In Susarro/arqastwb: Archaeoastronomy algorithms

Description

Star visibility information when certain star sets or rises at a given horizontal coordinate value

Usage

star_visibility(x, parms, horizontal_coordinate = "elevation",
  horizontal_star_time = "setting")

Arguments

x	Julian day
parms	Vector of strings containing the name of celestial body, geographic longitude, geographic latitude, geographic altitude and reference horizontal coordinate value
horizontal_coordinate	Horizontal coordinate (azimuth or elevation) to compare to a reference coordinate value or threshold
horizontal_star_time	"setting" or "rising". Only required if horizontal_coordinate=="elevation"

Value

Star visibility information

• date_star Julian day when the star reaches the specified horizontal coordinate value when rising or setting

• sky_visual_magnitude Visual magnitude of the sky at the specified horizontal coordinate value when the star is rising or setting

• azimuth_sun Azimuth of the Sun when the star reaches the specified horizontal coordinate value when rising or setting

• azimuth_star Azimuth of the star when it reaches the specified horizontal coordinate value when rising or setting

• altitude_sun Altitude of the Sun when the star reaches the specified horizontal coordinate value when rising or setting

• altitude_star Altitude of the star when it reaches the specified horizontal coordinate value when rising or setting

• star_visual_magnitude Visual magnitude of the star

#'

Examples

years<--2000:-1999
from<-str2jd(paste(years[1],"01","01",sep="-"))
to<-str2jd(paste(years[length(years)],"01","01",sep="-"))
star_name<-"epsilon orionis"
ee<-star_visibility(seq(from,to,1),
                    parms=c(star_name,
                            "42\u00b036'25\u0022N",
                            "5\u00b033'58\u0022W",
                            "782",
                            "2\u00b00'0\u0022"),
                    horizontal_coordinate="elevation", horizontal_star_time="setting")

ee<-star_visibility(seq(from,to,1),
                    parms=c(star_name,
                            "42\u00b036'25\u0022N",
                            "5\u00b033'58\u0022W",
                            "782",
                            "2\u00b00'0\u0022"),
                    horizontal_coordinate="elevation", horizontal_star_time="rising")

ee<-star_visibility(seq(from,to,1),
                    parms=c(star_name,
                            "42\u00b036'25\u0022N",
                            "5\u00b033'58\u0022W",
                            "782",
                            "-107\u00b022'33.866\u0022"),
                    horizontal_coordinate="azimuth")

ee<-star_visibility(seq(from,to,1),
                    parms=c(star_name,
                            "42\u00b036'25\u0022N",
                            "5\u00b033'58\u0022W",
                            "782",
                            "107\u00b022'33.866\u0022"),
                    horizontal_coordinate="azimuth")

Susarro/arqastwb documentation built on May 21, 2019, 10:28 a.m.