Complex sentence: Latitude can also be determined from Polaris, the northern pole star, however, since Polaris is not precisely at the pole, it can only estimate the latitude unless the precise time is known or many measurements are made over time.
Split into simpler sentences: Latitude can also be determined from Polaris, the northern pole star. However, since Polaris is not precisely at the pole, it can only estimate the latitude unless the precise time is known or many measurements are made over time.