Description Usage Arguments Value Author(s) References See Also Examples
The astronomical refraction is determined using the Sinclair's formula. This formula is based on the International Standard Atmosphere (ISA: which by the way does not mean the 'average' atmosphere;-). Due to the uncertainties aorund the atmsopheric condition of the Boundary Layers, the calcuated refractions will not be very accurate (say with 0.5deg). Below an Apparent altitude of -3.5deg, the Topocentric altitude is made equal.
1 | TopoAltfromAppAlt(AppAlt, TempE = TempDefault, PresE = PressureDefault)
|
AppAlt |
the Apparent altitude (deg), double |
TempE |
Temperature at height eyes (C, default=15C), double |
PresE |
Airpressure at height eyes (mbar, default=1013.25mbar), double |
TopoAlt thee Topocentric altitude (deg), double
Victor Reijs, lists@archaeocosmology.org
Bennett, G.G. 1982. 'The calculation of astronomical refraction in marine navigation', Journal of Inst. navigation, Vol 35: pp. 255-59.
http://www.archaeocosmology.org/eng/refract.htm
1 2 3 4 5 | TopoAltfromAppAlt(0,15,1013.25)
#-0.5598886443
TopoAltfromAppAlt(c(-4,-0.5,0,2,20))
#-4.0000000000 -1.1817229649 -0.5598886443 1.7010159897 19.9561578991
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