Hi all brothers dialists!
Who knows the exact time and the exact ecliptic longitude of the
earth's perihelion ?
I need these values to calculate myself the Equation of Time with this
formula I've obtained with a simple and traditional recipe : a little
bit of spherical geometry and another little bit of keplerian motion.
I submit it to your attention.
Maybe it is not so new or original as I believe, anyway is simple and
seems to work with good accuracy !
E.T. [minutes] = arctan { tan(M+L) } - arctan {cos O x tan
(M+L+180/pi x 2E x sin M ) }
_______________________________________________________
(average Earth
rotation speed in deg/min)
where :
M=(average Earth revolution speed in deg/day) x (number of days since
perihelion time)
L= perihelion longitude
O=obliquity of the ecliptic = 23,44 deg
E=terrestrial orbit eccentricity = 0,01672
and :
average earth rotation speed in deg/min = 0,250686
average earth revolution speed in deg/day = 0,985643
Thank you !
Alberto Nicelli
(45,5 N ; 7 E)
[EMAIL PROTECTED]
