The teutons called the moon "counter of time". Festivals where held at full moon or new moon. The year of Odinn was divided in eight months of one-and-a-half moon. At the end of the year, there was a period "between the years", which lasted a half moon. This created positive years and negative years. The positive years started with a full moon, the negative years started with a new moon.
So the year had twelve-and-a-half moon, which is longer than 365 days. Once in every nine years, all tribes send people to Uppsalir in Sweden. In this year, they took a part out of the last month. They also made sacrifices to the deities: nine men, nine dogs, nine wolves and nine horses were hung in a tree as a sacrifice.
The year starts with three-kings: Odinn, Freyr and Njordr. Then follows Car-naval, the car of the sea, which was devoted to Nerthus/Njord. Prince Car-naval was drowned as a gift to Jord. Ostara or easter followed next. It was devoted to Odinn. Then followed the Walpurgisnight. After that you had st john or Baldr's Balar with full or new moon after midsummer. Next there was the harvest-feast, then the slaughter-feast and finally Har-le-king or Halloween. Har is a nick-name for Odinn. In this feast the ulf-hedh-nar or werewolves dressed up like demons of the underworld to have a party. Between the years started with Sinterklaas (dutch), which is quite different from Santa Claus. Sinterklaas is Odinn, he rides on his horse over the clouds. Santa Claus is more like Ullr, who brings gifts from Upsalir.
To get back to the original question: In the year of Odinn, the moon decides when eastern or ostara begins. The moon is the counter of time.