Jupiter, Saturn, Neptune and Venus (JSNV) follow 179 year cycles which overlap in a similar way to the Saros cycle of eclipses, due to the interaction of several factors with similar orbital wavelengths.

An example of the overlapping cycles of the conjunctions of these four planets is as follows. In 54AD, a Jupiter Saturn conjunction followed their conjunctions with Neptune by two months for Jupiter and a year for Saturn. In successive 179 year repeats of this event, in 232-3, 411, 590, 769, 948, 1127, 1306-7, 1484-7, 1663-7, 1842-6, and 2021-5, the gap between the JS conjunction and their respective conjunctions with Neptune steadily decreases to a point where these three are near exactly conjunct in 769, after which JS meet an increasing time before they reach Neptune. This pattern overlaps with other families of JSNV conjunctions, for example 1344-5, 1523-4, 1702-3, 1881-2, 2060-1. This 1344-2060 group has 1523 as the year of closest JSN alignment, with the JS conjunction precessing against the JN and SN dates as in the 54-2021 series. In all cases each event is about 30° further along the ecliptic than its predecessor 179 years before. These families of repeating conjunctions, of which Venus is also a part, are produced by the small difference in orbital periods with 9 x JS=178.7 ~= 14 x JN = 178.9 ~= 5 x SN = 179.3 years. Interestingly, these orbital JSN periods produce a clear gravitational pattern in the wave function of the solar system barycentre as shown here.

The similarity with the Saros cycle is that eclipse families begin with inexact alignments producing short eclipses near the earth’s poles, but as the alignment improves each family of eclipses grows in length and width and migrates towards the equator and the other pole. Each family returns every 18 years, and there are about 40 simultaneous Saros eclipse families.