Inex
The Inexzyklus is an eclipse cycle with a period ( the Inexperiode ) of about 29 years less 20 days.
Every single Inexzyklus theoretically contains about 809 eclipses and is estimated at approximately 23,410 years long. The Dutchman George van den Bergh has rediscovered these previously recognized cycle and given him the name Inex cycle.
Van den Bergh also created what he called the Saros - Inex panorama as an attempt to recognize all kinds of darkness cycles easier than it is possible with a darkness - Canon.
Determination of Inexperiode
Continued fraction calculation
The number of eclipses contained in a cycle is greater, the more accurately the existing synodic months of darkness period is an integer multiple of half drakonitischen months. Among the number of pairs found with the aid of continued fraction calculation, the pair of 358 synodic months and 777 months half drakonitischen ( 388.5 drakonitische months) the Inexperiode.
Van den Bergh's method
Van den Bergh, the short texts were unknown in earlier writings about the nameless before him cycle. He turned to even a relatively simple continued fraction calculation, but found the Inexperiode through extensive evaluation of the Canon of Eclipses of Theodor Oppolzer.
Van den Bergh sought from the Canon out those eclipses that exceed the assumed ± 11 ° with darkness limit on just the most under offer or. These eclipses follow in about 29 years less 20 days, the Inexperiode. He made it also clear that the node distances differ by about 0.0411 °, the node distance change in a Inexzyklus.
From the entrance (go IN ) of these eclipses found in the present between the darkness - limits zone for central eclipses and from the leakage (go EX) formed van den Bergh 's name INEX.
The eclipses found looked van den Bergh, not as part of any cycle number (which is possible in principle ), but as belonging to each one Saros cycle. This approach led directly to his Saros - Inex panorama.
Properties of a Inexzyklus
As the number of half drakonitischen months is odd ( 777 ), find the darkness unlike a Saros cycle alternately near the ascending or the descending lunar node instead. A cycle consists of two nested rows darkness, the one from south to north, the other runs from north to south of those.
The node distance change is positive ( 0.0411 °). The first, taking place near the ascending node eclipses found in Antarctica, the last in the Arctic instead of wandering reversed the descending node.
The 550 will take place in the middle of the cycle duration solar eclipses are total or annular -total at irregular intervals because the anomalistic month, unlike the Saros cycle, does not fit into the Inex - pattern ( the Earth-Moon distance varies during a Inexzyklus ).
Saros - Inex panorama
Van den Bergh wanted to help finish his Saros - Inex panorama of the strife between the advocates of Saros or the Inexzyklus. He offered it as a possibility, thus can be easier than with a darkness - Canon detect all kinds of darkness cycles.
In the panorama of the Canon is transferred to the eclipses of the Oppolzer. It is an up and down " frayed " table whose columns each contain all eclipses of Saros cycle. The lines form the darkness Inexreihen. Oppolzer Canon was eight times too short to about 800 eclipses, the length of a Inexzyklus extending the rows. Also with the help of modern darkness catalogs that is not possible by far.
The numbers of the columns have become established as the number of each Saroszyklen.
Importance of Inexzyklus
The Inexzyklus is like any other cycle, a theoretical result from a continued fraction calculation. With average values for the sidereal month and the drakonitischen this leads to Inexperiode and node distance change within the Inexzyklus. However, the latter varies in reality considerably against the calculated average value of 0.0411 °. You decreases in 3000 years from 0.0722 ° to 0.0294 °. The change is more than 100 % of the calculated average value. This disproportion in a relatively short time and the very large predicted cycle duration not speak for a significant darkness cycle, as might be assumed from the theoretical mean values.
The Inexzyklus has indirectly get practical significance, because van den Bergh undertook the numbering used today is of the individual Saroszyklen in Saros - Inex panorama.