The Longitude of the Mizusawa International Latitude Observatory

Abstract

The redetermination of the longitude of Mizusawa was pursued at Mizusawa Observatory since 1953 till 1955 for the purpose of the investigation of the longitude variation at Mizusawa. The final results are;
9^h24^m31^s.411 E
For convenience the following value of the longitude is adopted as the official one;
9^e24^m31^s. 400 E
In comparison with the former determination in 1902, it can be seen that there was no displacement of Mizusawa since 1902 till now, which is the negative answer to the discussion about the existence of the eastward flow of the Japan Island . Whereas recent results of time observations with PZT show us the apparent westward drift of Mizusawa longitude amounting about 8 ms a year.