Location, Location, Location
Unlike observing from a fixed position on land, when underway your ship-observatory is constantly moving. The latitude, longitude and time zone need to be constantly updated in your software, planisphere or star charts, as we learned in the last chapter. Your cruise may stay in a single geographical area, like the Caribbean, or go from port to port in one country or several close by countries, again a relatively compact area. But if you are on a transoceanic cruise that is crossing the Atlantic or Pacific, or one of the “Grand Voyages” that can last 30 days or longer, you will be potentially changing hemispheres and undergoing large shifts in latitude and longitude. This can radically alter the view of the sky.