But since an ellipse can always be constructed with a given centre so as to touch a given line at a given point, and to have a given value of ab(=h/-~ u) we infer that the orbit will be elliptic whatever the initial circumstances.
Regular ellipse about 22 m.
It is the envelope of circles described on the central radii of an ellipse as diameters.
The largest is an ellipse of about 60 by 66 ft., but most of the sesi have a diameter of 20-25 ft.
The star thus appears to describe a small ellipse in the sky, and the nearer the star, the larger will this ellipse appear.