that Maunder is still a puzzle. Not sure the SC-10 provides the key.

here is the cycle perspective:

we have the short term cycles of 10, 11 and 12 years. The 11 year cycle is rigid and overrides the others.

The three cycles produce beats of

10+11=96 years (and 2x96=192)

11+12=168 years

10+12=61 years (and 3x61=183)

And finally we have the Uranus-Neptun cycle of 172 years that normally produce two or three disturbances, separated by ~40 years

So every ~96 years the short 10 year cycle has to surrender to the 11 year cycle. That causes the phase-failure and a Gleissberg low, easily seen as weak sunspot cycles.

And every ~168 years the 12 year cycle has to surrender to the 11 year cycle, which is not so easily seen in the sunspot cycles (normally results in stronger sunspot cycle)

And the 10 and 12 year cycle fights each other and one of them surrender each ~61 years.

-either the 10 year cycle, which results in a Gleissberg low

-or the 12 year cycle

And the 10 year cycle surrenders near twice as often as the 12 year cycle

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So every ~61 years something happens:

~1580: strong cycles

~1640: Gleissberg low (ideal 1600)

~1700: Gleissberg low (ideal 1695)

~1760: strong cycles

~1820: Gleissberg low (ideal 1790)

~1880: Gleissberg low (ideal 1890)

~1945: strong cycles

~2005: Gleissberg low (ideal 1980)

~2065: Gleissberg low (ideal 2075)

So the actual Gleissberg low is often somewhat shifted in time, depending on where the 61 year cycle is.

last centuries these cycles have produced pairs of Gleissberg lows (or cycles). And every second cycle (high) is strong/weak (and long/short)

Then we have the grand minima. When we have the right configuration with regards to the two other cycles (168 and 172) we get a grand minima.

The grand minima seems to be a possibility at the first Gleissberg low of the pair (like 1640, 1820 and 2005)

AND the first Gleissberg low has to happen at the "correct" interval of the 168 year cycle, and probably at the first of the three disturbances in from Uranus-Neptun in the 172 year cycle (phew)

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OK

The first Gleissberg in Maunder obviously fulfilled this criterias (and the first UrNe-disturbance was in 1610)

I also assume that the Spörer and Wolf-minima fullfilled these criterias.

Spörer: I go back 2x60 years from 1580 and get year 1460. That should be the first Gleissberg. But 60 years earlier is year 1400.

And I go back 2x96 years from 1600 and get year 1408.

So did the Gleissberg happen near year 1400 or 1460?

The 168 year cycle had to be right.

1645-1460=185 years

1645-1400=245 years

There were only two big disturbances from UrNe, around year 1470 and 1510

So the probable time for a grand minimum seems to be in the years around 1460 to 1520. And it may start a bit earlier and end a bit later.

Wolf: I begin at the other end this time. The UrNe disturbances were around years 1290, 1325 and 1360 (weak disturbance).

2x168 years earlier than 1645 is 1309

So we could look for grand minima setup around years 1290-1360

1400-60=1340, and 1340-60=1280

1408-96=1312

So this setup is different, because we have only one Gleissberg and not a pair.

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The Dalton: 1645+168=1813

The Ur-Ne disturbances in years 1790, 1830 and 1870 (weak)

A Gleissberg in ~1790-1820.

This looks very much like a grand minimum setup, but it didnt materialize. Sunspotcycle number 7 shot up just ahead of the disturbance, while SC-9 didnt make it.

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Now: 1813+168=1981

The UrNe disturbances are in years 1970 and 2010

A Gleissberg around year 2005 and the next in 2065

This doesnt look like an ideal grand minimum setup.

We are a bit too late in the 168 year cycle, meaning that the two tidal cycles of 11 and 12 years are in phase (prevensts grand minima?)

And we are at the second UrNe disturbance (a very weak on in years 2045)

But we do seem to have two narrow spaced Gleissberg lows, and should anyway have (mostly) weak sunspot cycles in the years 2010-2080

We do have pretty good knowledge of two setups (Maunder and Dalton), where only one of them produced a grand minima. By analysing these two setups I may find some clues for a better understanding of what triggers the catastrophe/grand minima...

bb