At periastron the disturbing force will, therefore, increase the Apastron distance by an enormous amount, while at Apastron it increases the periastron distance by a very small amount.
"The Story of the Heavens"
Robert Stawell Ball
This pace, however, has not been maintained, for, their periastron having occurred in 1750, they travelled more rapidly in the last century than they are doing at present, and, as their orbits are so eccentric that when at Apastron the stars are twice as remote from each other as at periastron, they will for the next three and a half centuries continue to slacken their pace, until they shall have reached the most remote points of their orbits, when they will again begin to approach with an increasing velocity; so that the time in which an entire revolution can be accomplished will not be much less than 1,000 years.
"The Astronomy of Milton's 'Paradise Lost'"
Thomas Orchard
The pair travel in an orbit from fourteen to forty-two times the radius of the Earth's orbit; so that when at Apastron they are three times as distant from each other as when at periastron.
"The Astronomy of Milton's 'Paradise Lost'"
Thomas Orchard