Page:Dante and the early astronomers (1913).djvu/45

 Mean Anomalistic Month: period between perigee and perigee (vide infra)

Days. Hrs. Mins. Sees.

27 13 18 37.4


 * —Mean Synodic Revolution: period between two successive conjunctions with the sun, and mean zodiacal revolution: period of revolution round the zodiac.

Mean Synodic Revolution. Mean Zodiacal Revolution. Mercury 116 Days 1.0 Years

Venus 584 „ 1.0 „

Mars 780 „ 1.88 „

Jupiter 399 „ 11.86 „

Saturn 348 „ 29.46 „


 * 50.25 seconds of arc in one year; that is, 360 degrees (a revolution among the stars of the zodiac) in 25,800 years nearly.