Ephemeris vs. Stellarium

Hi there. I am confused, because when I try to verify the Mercury stations in my birth year ephemeris, it does not seem to agree with Stellarium's (a planetarium program) Greatest Elongation of Mercury. Specifically, according to the Astrodienst ephemeris online, Mercury stationed direct on March 27, 1973, but Stellarium shows greatest elongation (where it appears to turn around and reached it's farthest point from the sun during that part of that cycle) on April 10th or 11th. Can anyone shed some light on my confusion? Thanks so much, Noah

Okay figured it out. For some reason I was assuming that Mercury would turn around at its farthest point from the sun. While that may be true if the Sun were stationary, the sun clips along at a pretty good rate. Therefore, the swing around is not so simple, and is quite a bit different on the other side of it's swing.