The FS2 goto system on my Zeiss 1B mount is accurate enough to slew
to any object to appear almost center field of a TeleVue 20mm
eyepiece at 120x (<30').
The only exception I found is the planet Uranus.

At 06-10-07 at 19:20 UT The FS2 goto slewed to Uranus at RA 23h11m7,
DEC -6°03'. The planet was not found in my telescope field. I Found
Uranus though, near the edge of the field of my finder, so I
adjusted the telescope by the hand box buttons. With Uranus center
field the hand box displayed RA 23h08m0 and DEC -6°22', almost 1
degree off!

In Starry Night Pro Uranus was calculated at the same time at RA
23h08.5m and DEC -6°23', almost the same as the real position at the
hand box display.

This mistake cannot be the result of improper aiming of the polar
axis, as except for Uranus I did not notice any mistake in slewing to
objects, neither at other planets nor fixed objects.

Is this the result of the FS2-calculation of undisturbed orbits? The
FS2 Instruction manual says: "The calculation of the planet
coordinates is based on undisturbed orbits and is therefore not a
precise calculation. However, the calculation is precise enough to
find the planets."

My question: Is Uranus' orbit really that badly disturbed? In other
words: dit I find out what Adams and Leverrier discovered two
centuries ago? Or is Uranus' orbit simply not properly calculated in
the FS2?

Regards,
Pieter