Theory of Norman Lockyer
Joseph Norman Lockyer researched on Parthenon, the temple of Karnak and the Stonehenge. According to his research, he states that the three monuments are interrelated to each other. During the 20th century, astro- archaeologist, Norman Lockyer, raised some theories about the Stonehenge. According to his theories, he states that Stonehenge and other megalithic1 constructions were used as ancient observatories. He also made a theory that mid-summer was determined based on the Heelstone.
From his research on Stonehenge, Sir Norman Lockyer tried to calculate back from the point where the sun rose on the year 1901 and determined whether the heel stone is still in the correct position. He then made the necessary calculations. However, the calculations he made was flawed and the results was considered meaningless.

Norman Lockyer
Theory of Mark Parker Pearson
According to Mark Parker Pearson, the leader of the Stonehenge Riverside Project, he claimed that the Stonehenge was associated with the burial of people ever since it was created. He claimed people was buried in the Stonehenge since the beginning of the creation of the Stonehenge up to the third millennium BC.

Mark Parker Pearson
Theory of Hawkins, G. S
According to professor Gerald Stanley Hawkins, the Aubrey holes located at the Stonehenge were used to count the years of a 56-year cycle, the motion of the moon, and the occurrence of eclipses. However, there are several controversies of how the Stonehenge was used to calculate the period of years. Some other archaeologist disagree with the theory of Hawkins and states that the Stonehenge was used to count the years in a period of a 56-month cycle and not a period of 56-year cycle.