Atri's Solar Eclipse
We have identified all solar eclipses that have occurred three days before autumnal equinox somewhere on earth at the latitude of 25 degrees. Any one of these thirteen can be Atri’s eclipse because of uncertainties in earth’s position or Delta T. To narrow the choice further, we need to decide on what the true deltaT would be corresponding to period concerned. It would appear that Knowledge of Delta T is still evolving, with many contemporary models proposed. A study of the Delta T used by Espenak (Ref 5) reveals scatter in Delta T he has used for his eclipses. His delta T’s are plotted as function of Julian year. It shows that some follow Meeus’s model and some Stephenson’s model. Some switch between the two. One would expect delta T being an integral function to be monotonic and smooth always slowing down. But two of his data shows speeding of earth. Thus modeling of Delta T is still not perfected to the degree of extreme confidence.
We now look at Atri’s solar eclipse candidates, with delta T adjusted to occur at Chitrakoot. Only one amongst these is a serious candidate. Recent Irish megalith eclipse appears to provide some corroboration of an eclipse in form of stone carvings. Other historical eclipses do not have such corroboration. In further analysis, we accept Stephenson (1986) model and Meeus’s mode as representative models very near each other
Stephenson 1986 model based analysis:
If we accept Stephenson 1986 model, best Atri’s eclipse purely from Delta T point of view are six candidates viz., 1131BC, 1476 BC, 1522 BC, 2676 BC, 4286 BC and 4965 BC dates
If we were to impose Stephenson’s model plus 3day autumnal equinox requirement, then the candidates drop to five candidates viz., 1131BC, 1522 BC, 2676 BC, 4286 BC and 4965 BC.
IF were to demand Stephenson’s Delta T model plus 3day to Autumnal equinox plus 100% eclipse at maximum, then the list drops to two candidates viz., 1131BC and 1522 BC.
Meeus’s Delta T Model
There are only two candidates if we were to use Meeus’s delta T model. They are the 1476 BC eclipse and the 4677 BC eclipse.
However, when we impose condition that the eclipse be 100% and occur 3days before equinox, then only one candidate viz., 4677 BC eclipse meets tall requirements.
All Known Delta T models
If we were to only go by 3day requirement, following ten viz., 1131BC, 1522 BC, 1913 BC, 2676 BC, 3048 BC, 3439 BC, 4202 BC, 4286 BC, 4593 BC and 4676 BC would qualify
However, if we were to only go by 3day requirement plus 100% eclipse the following five eclipses viz., 1131BC, 1522 BC, 3439 BC, 4202 BC and 4647 BC would qualify.
