Don't even know what to call this post!

True, the title says it all! But, what I am looking for, hopefully there is an answer.

Does the Moon follow a 19 year pattern in that, e.g. on this date, in 19 years time, it will be the same phase at the same position in the sky?

I want to know what this is called, and also, do any other planets, notable Venus, follow the same type pattern (not necessarily by phase, but on visibilty and position - like its own 'solstice')?

Cheers,

Seanie.

Hi Seanie,

Yes, there is such a cycle. It's called the Metonic Cycle and was named after Meton of Athens (ca. 440 BC) who noticed that 235 lunar months made up almost exactly 19 solar years. It was the basis for the Greek calendar until the Julian calendar was introduced in 46 BC. Since 12 lunar months equal 354.367 days, about 11 days less than a solar year, an additional lunar months were added to synchronize the cycle. These were added in years 3, 5, 8, 11, 13, 16, and 19 of the cycle. The Metonic cycle was extended by Callippus to 4 19-year cycles, which is known as the Callipic cycle.

Cheers,

Gary Nugent
www.nightskyobserver.com
www.lunarphasepro.com

Thanks Gary! Didn't know any of that - might come in handy at a future tabel quiz!

Have you any info on Venus doing something similar?

I'm not aware of any Venus cycles. Maybe someone else knows?

This also comes under the Babylonian 19 year cycle which was approx 380 BC, I think one then led into the other..etc

Is this a fluke or some sort of gravitationally induced cycle, like the Mercury day/year relationship.

BTW, Mercury has 3 days for every 2 years :shock: