Celestial navigation using Jupiter - Essay Example

They suggested that the disparity in time amid the observed and the prospective time at a standard meridian would enable longitudinal meridian to be identified. The innermost moons had an orbital of around one and a quarter days and callsito. The outermost had a period of about 17 (Watson,13). It is through regular observation that they understood their motions developing comprehensive tables of predictions. The method of measuring longitude involves drawing comparisons between the planets and the moon thus drawing rough estimates of the longitude.

The method by Galileo articulated that it took the earth twenty four hours to travel 360 degrees rotation, at any point. His meant that at every point the earth travels fifteen degrees of longitude in every hour (Watson, 15). They thus carried accurate clocks to the see where two clocks were compared one clock based on the home port and the other in the ship. It was mandatory for the clock in the ship to be reset to local noon time daily. The difference in time was an indication of the longitudinal difference travelled.

One hour represented a fifteen degree in longitude. Longitude is calculated in degrees east or west of the prime meridian, with 180 degrees on either side of the prime meridian. . Latitudes are equidistant from each other thus the term parallels (Silvio, 82). In the ancient times sailors used the latitudes in their navigation. It was during the Ptolemy era when a grid system for the earth was created. The earth, a circle, was divided into 360 degrees. Each degree was issued with one hour, and each minute comprised 60 seconds.

It was in his book geography where the coordinated were published. The ancient sailors used sextants in measuring latitudes. A sextant is a navigational appliance that measures the angle of elevation of any celestial body (sun and the moon). This was done in an attempt to locate ones direction. The instrument was thus used to determine the angle linking two objects. A sextant spans at 60 degree which is a sixth of a circle thus the name. In measuring latitude, at the equator which has a zero degree latitude the Polaris is in horizon with zero degrees altitude.

The elevation in the angle of Polaris above the horizon indicated a direct measure of terrestrial latitude. This means that in case the angle of Polaris was measured by a navigator and found to be 10 degrees from the horizon, then the ship is ten degrees north of the equator. At times they determined the latitudes through the directions travelled by stars over time. They articulated that if the stars rise from the east and they travel straight upwards then one is ate equator. In case the stars drifted south then one is at the north of the equator.

This can be postulated to occur due to the movement of the earth in an orbit around the sun. The other method of measuring longitude was the use of the marine chronometer. This involved the use of a time piece that was to be carried in a ship and would maintain the correct reference time