On the effects of lunar tides in the Tianjin latitude observations

In this paper we have analysed the effect of the lunar tide on the latitude observations of 25260 star-pairs with the zenith telescope, ZTL-180 of Tianjin Latitude Station during 1960–1966. For the M₂ wave, we found an amplitude of 0.0108 and hence a value of 1 + k ? 1 = 1.34. When the effect of the ocean tide is subtracted, the value of 1 + k ? 1 is reduced to 1.315. This is in very good agreement with the value 1.31, deduced by geophysicists for the Asia region.