Dear Francois, >I can't find what is wrong... Is it t0 (3 january 1950) ? is it w ? >For w, I use : > > w = 101°13'15" + 6189".T >with T the number of days ( from the 1 january 1900 at 0h ) divided by >365.25. >
I think your problem is the definition of T. The longitude of perihelion increases very slowly -- by less than 2 degrees per century. So it should be defined as the number of days from 1 Jan 1900 divided by 36525 days (instead of 365.25 days). Otherwise your method seems okay. Best regards, Roger Sinnott Sky & Telescope
