Function: solar-ephemeris-time

solar-ephemeris-time is a byte-compiled function defined in solar.el.gz.

Signature

(solar-ephemeris-time TIME)

Documentation

Ephemeris Time at moment TIME.

TIME is a pair with the first component being the number of Julian centuries elapsed at 0 Universal Time, and the second component counting Universal Time hours. For instance, the pair corresponding to November 28, 1995 at 16 UT is
(-0.040945 16), -0.040945 being the number of Julian centuries elapsed between
Jan 1, 2000 at 12 UT and November 28, 1995 at 0 UT.

Result is in Julian centuries of ephemeris time.

Source Code

;; Defined in /usr/src/emacs/lisp/calendar/solar.el.gz
(defun solar-ephemeris-time (time)
  "Ephemeris Time at moment TIME.
TIME is a pair with the first component being the number of Julian centuries
elapsed at 0 Universal Time, and the second component counting Universal Time
hours.  For instance, the pair corresponding to November 28, 1995 at 16 UT is
\(-0.040945 16), -0.040945 being the number of Julian centuries elapsed between
Jan 1, 2000 at 12 UT and November 28, 1995 at 0 UT.

Result is in Julian centuries of ephemeris time."
  (let* ((t0 (car time))
         (ut (cadr time))
         (t1 (+ t0 (/ (/ ut 24.0) 36525)))
         (y (+ 2000 (* 100 t1)))
         (dt (* 86400 (solar-ephemeris-correction (floor y)))))
    (+ t1 (/ (/ dt 86400) 36525))))