Rising and Setting of Heavenly Bodies

A thorough understanding of the rising and setting of heavenly bodies is essential for ship’s navigators. This is not only in order to plan the time at which star sights may be taken, but more importantly, for planning operations which require total darkness, twilightTwilight or moonlight. Today, a number of sources of this information are available, but it remains essential that specialist navigators understand the theory and are able to complete the calculations manually.