era.ldsun.md

eraLdsun

p1 = ERFA.ldsun(p, e, em)

Deflection of starlight by the Sun.

Given:

   p      double[3]  direction from observer to star (unit vector)
   e      double[3]  direction from Sun to observer (unit vector)
   em     double     distance from Sun to observer (au)

Returned:

   p1     double[3]  observer to deflected star (unit vector)

Notes:

1. The source is presumed to be sufficiently distant that its directions seen from the Sun and the observer are essentially the same.

2. The deflection is restrained when the angle between the star and the center of the Sun is less than a threshold value, falling to zero deflection for zero separation. The chosen threshold value is within the solar limb for all solar-system applications, and is about 5 arcminutes for the case of a terrestrial observer.

3. The arguments p and p1 can be the same array.

Called:

   eraLd        light deflection by a solar-system body

This revision: 2016 June 16

Copyright (C) 2013-2021, NumFOCUS Foundation. Derived, with permission, from the SOFA library.