elev | R Documentation |
Calculates source elevation and azimuth in degrees given declination, hour angle, and observatory latitude.
elev(dec.sou = "33d 09m 35.0s", ha = 0, lat.obs = "38d 25m 59.2s") azimuth(dec.sou = "33d 09m 35.0s", ha = 0, lat.obs = "38d 25m 59.2s")
dec.sou |
Source declination (string) |
ha |
Hour angle (decimal hours) |
lat.obs |
Observatory latitude (string) |
Enter latitude as s text string with fields separated by characters d, h, m, s, a colon, or a comma, e.g. '38d25m59.2s' or '38, 25, 59.2' or '38:25:59.2' or '38:25.987' for the Green Bank Telescope. Spaces are removed in input conversion. Decimal values for degrees or minutes are allowed. Trailing missing values are taken as zero.
Source elevation or azimuth (E from N) in degrees.
Geometrical calculation only, no corrections for refraction, aberration, precession, etc.
Andrew Harris
"Astrophysical Formulae," K.R. Lang, Springer c. 1986, 5-45
dms2rad
, hms2rad
for input formats,
ut2ha
to convert UT to hour angle.
# Maximum elevation at Green Bank elev(dms2rad('-28, 20')) # Maximum elevation at Mauna Kea elev(dms2rad('-28, 20'), 0, '19:49') # Plot elevation and azimugh vs. hour angle ha <- seq(0, 24, 0.25) el <- elev('30d 33m 22s', ha) plot(ha, el, t='l', col=4) az <- azimuth('30d 33m 22s', ha) plot(ha, az, t='l', col=4) # Plot elevation and azimuth vs. UT (using many defaults) h.ut <- seq(0, 24, 0.25) el <- elev(dec.sou='30d 33m 22s', ha=ut2ha(hr=h.ut)) plot(h.ut, el, t='l', col=4) az <- azimuth(dec.sou='30d 33m 22s', ha=ut2ha(hr=h.ut)) plot(h.ut, az, t='l', col=4)
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