R/transit_table.R

In helixcn/ephem: Creating figures for astronomical almanac

transit_table <-
function(start.JD, days = 30) {
  JD.dat <- seq(start.JD, start.JD + days + 1, by = 1)
  transit <- rep(NA, length(JD.dat))
  dat.table <- data.frame(JD.dat)

  for (i in 1:days) {
    dat.table[i, 2] <- planetRTScalc2(planet = "mercury", JD.dat[i], longitude = 0,
               latitude = 0, zone = 0, type = "transit") - dat.table[i, 1]

    dat.table[i, 3] <- planetRTScalc2(planet = "venus", JD.dat[i], longitude = 0,
               latitude = 0, zone = 0, type = "transit") - dat.table[i, 1]

    dat.table[i, 4] <- planetRTScalc2(planet = "mars", JD.dat[i], longitude = 0,
               latitude = 0, zone = 0, type = "transit") - dat.table[i, 1]

    dat.table[i, 5] <- planetRTScalc2(planet = "jupiter", JD.dat[i], longitude = 0,
               latitude = 0, zone = 0, type = "transit") - dat.table[i, 1]

    dat.table[i, 6] <- planetRTScalc2(planet = "saturn", JD.dat[i], longitude = 0,
               latitude = 0, zone = 0, type = "transit") - dat.table[i, 1]

    dat.table[i, 7] <- planetRTScalc2(planet = "uranus", JD.dat[i], longitude = 0,
               latitude = 0, zone = 0, type = "transit") - dat.table[i, 1]

    dat.table[i, 8] <- planetRTScalc2(planet = "neptune", JD.dat[i], longitude = 0,
               latitude = 0, zone = 0, type = "transit") - dat.table[i, 1]

    dat.table[i, 8] <- planetRTScalc2(planet = "neptune", JD.dat[i], longitude = 0,
               latitude = 0, zone = 0, type = "transit") - dat.table[i, 1]

    dat.table[i, 9] <- sunRTScalc2(JD.dat[i], longitude = 0,
        latitude = 0, zone = 0, type = "transit") - dat.table[i, 1]

    res.date <- Julian2Date(dat.table[i, 1])
    dat.table[i, 10] <- res.date$Y
    dat.table[i, 11] <- res.date$M
    dat.table[i, 12] <- res.date$D
  }
  dat.table <- na.omit(dat.table)
  colnames(dat.table) <- c("JD", "Mercury", "Venus", "Mars", "Jupiter", "Saturn",
     "Uranus", "Neptune", "Sun", "Year", "Month", "Day")
  return(dat.table)
}