### SLA_ECOR

RV & Time Corrns to Sun

ACTION:
Component of Earth orbit velocity and heliocentric light time in a given direction.
CALL:
CALL sla_ECOR (RM, DM, IY, ID, FD, RV, TL)
##### GIVEN:
 RM,DM R mean $\left[\phantom{\rule{0.3em}{0ex}}\alpha ,\delta \phantom{\rule{0.3em}{0ex}}\right]$ of date (radians) IY I year ID I day in year (1 = Jan 1st) FD R fraction of day

##### RETURNED:
 RV R component of Earth orbital velocity (km s${}^{-1}$) TL R component of heliocentric light time (s)

NOTES:
(1)
The date and time is TDB (loosely ET) in a Julian calendar which has been aligned to the ordinary Gregorian calendar for the interval 1900 March 1 to 2100 February 28. The year and day can be obtained by calling sla_CALYD or sla_CLYD.
(2)
Sign convention:
• The velocity component is +ve when the Earth is receding from the given point on the sky.
• The light time component is +ve when the Earth lies between the Sun and the given point on the sky.
(3)
Accuracy:
• The velocity component is usually within 0.004 km s${}^{-1}$ of the correct value and is never in error by more than 0.007 km s${}^{-1}$.
• The error in light time correction is about $0$$s$$\phantom{\rule{-3.28502pt}{0ex}}.03$ at worst, but is usually better than $0$$s$$\phantom{\rule{-3.28502pt}{0ex}}.01$.

For applications requiring higher accuracy, see the sla_EVP and sla_EPV routines.