The following functions are used to calculate positions of fixed stars.
swe_fixstar2_mag(starname)
swe_fixstar2(starname, jd_et, iflag)
swe_fixstar2_ut(starname, jd_ut, iflag)Star name as string ("" for no star)
ET Julian day number as double (day)
Calculation flag as integer, many options possible (section 2.3)
UT Julian day number (day)
swe_fixstar2_mag returns a list with named entries: return status flag as integer,
starname updated star name as string, mag magnitude of star as double, and serr for error message as string.
swe_fixstar2 returns a list with named entries: return status flag as integer,
starname updated star name as string, xx star phenomena as numeric vector, and serr error message as string.
swe_fixstar2_ut returns a list with named entries: return status flag as integer,
starname updated star name as string, xx star information as numeric vector, and serr for error message as string.
Calculate visible magnitude (Vmag) of star.
Compute information of star using ET.
Compute information of star using UT
Section 4 in http://www.astro.com/swisseph/swephprg.htm. Remember that array indices start in R at 1, while in C they start at 0!
data(SE)
swe_fixstar2_mag("sirius")
#> $return
#> [1] 0
#>
#> $starname
#> [1] "Sirius,alCMa"
#>
#> $mag
#> [1] -1.46
#>
#> $serr
#> [1] ""
#>
swe_set_topo(0,50,10)
swe_fixstar2("sirius",1234567,SE$FLG_TOPOCTR+SE$FLG_MOSEPH+SE$FLG_EQUATORIAL)
#> $return
#> [1] 34820
#>
#> $starname
#> [1] "Sirius,alCMa"
#>
#> $xx
#> [1] 64.65734 -17.80520 547924.62574 0.00000 0.00000
#> [6] 0.00000
#>
#> $serr
#> [1] ""
#>
swe_fixstar2_ut("sirius",1234567,SE$FLG_TOPOCTR+SE$FLG_MOSEPH+SE$FLG_EQUATORIAL)
#> $return
#> [1] 34820
#>
#> $starname
#> [1] "Sirius,alCMa"
#>
#> $xx
#> [1] 64.65729 -17.80518 547924.62843 0.00000 0.00000
#> [6] 0.00000
#>
#> $serr
#> [1] ""
#>