Transit of Uranus from Neptune

A transit of Uranus from Neptune occurs when Uranus passes directly between the Sun and Neptune. Uranus can then be seen as a small black disk edging slowly across the disk of the Sun.

This is the rarest of all transits involving the eight official planets, owing to the long synodic period of 172 years, the very small apparent diameter of the Sun (1.07 arc-minutes) as seen from Neptune, and the mutual inclination of the two orbits. (Transits from Pluto are likely to be rarer still, due to the inclination of its orbit.)

The VSOP87 model as implemented in Stellarium finds a transit of Uranus from Neptune on 6 August 46,915. However, VSOP87 claims an accuracy of one arc-second for 6000 years before and after J2000, according to the Stellarium user manual, and 46,915 falls well outside that range. It is unclear, then, whether there is really a transit at that time.