Transit of Venus at 4.30am in Inverurie ........

A transit occurs when Venus reaches conjunction with the Sun at or near one of its nodes-the longitude where Venus passes through the Earth's orbital plane (the ecliptic)-and appears to pass directly across the Sun. Although the inclination between these two orbital planes is only 3.4°, Venus can be as far as 9.6° from the Sun when viewed from the Earth at inferior conjunction. Since the angular diameter of the Sun is about half a degree, Venus may appear to pass above or below the Sun by more than 18 solar diameters during an ordinary conjunction.

Sequences of transits repeat every 243 years. After this period of time Venus and Earth have returned to very nearly the same point in their respective orbits. During the Earth's 243 sidereal orbital periods, which total 88757.3 days, Venus completes 395 sidereal orbital periods of 224.701 days each, equal to 88756.9 Earth days. This period of time corresponds to 152 synodic periods of Venus.
The pattern of 105.5, 8, 121.5 and 8 years is not the only pattern that is possible within the 243-year cycle, because of the slight mismatch between the times when the Earth and Venus arrive at the point of conjunction. Prior to 1518, the pattern of transits was 8, 113.5 and 121.5 years, and the eight inter-transit gaps before the AD 546 transit were 121.5 years apart. The current pattern will continue until 2846, when it will be replaced by a pattern of 105.5, 129.5 and 8 years.
Thus, the 243-year cycle is relatively stable, but the number of transits and their timing within the cycle will vary over time.
Well thats a bit hard. Captain Cook did it well though.
My alarm is set.