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Posts Tagged ‘Pilgrims’

11/27/2014 – Ephemeris – The voyage of the Mayflower

November 27, 2014 Comments off

Ephemeris for Thanksgiving Day, Thursday, November 27th.  The sun will rise at 7:54.  It’ll be up for 9 hours and 10 minutes, setting at 5:05.   The moon, 2 days before first quarter, will set at 10:51 this evening.

We are regaled with stories of the first Thanksgiving dinner between the Native Americans and the Pilgrims.  The Mayflower was headed for the Virginia Colony but were diverted by a storm.  Their first landfall in the New World was Newfoundland, where they picked up supplies.  Fulling intending to head south to Virginia, the passage became too hazardous, so they put into Cape Cod and there they stayed.  Back in those days the ship’s position was determined rather crudely.  Latitude was measured by the height of the north star and the sun at noon.  Distance and speed were measured with a log thrown overboard with a rope with knots in it.  The knots counted over a period of time gave the ship’s speed.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

Mayflower

Credit: Scholastic

11/22/2012 – Ephemeris – Celestial navigation in the days of the Pilgrims

November 22, 2012 Comments off

Ephemeris for Thanksgiving Day, Thursday, November 22nd.  The sun will rise at 7:48.  It’ll be up for 9 hours and 19 minutes, setting at 5:08.   The moon, 2 days past first quarter, will set at 2:58 tomorrow morning.

Back in the days of the Pilgrims navigation was much less certain than it is today.  At the mercy of the winds and weather, sailing took a lot of courage.  Celestial navigation took the form of measuring the altitude of the pole star Polaris at night and the sun at noon.  That and tossing a log overboard attached to a rope with knots at regular interval to gauge their speed and progress.  That’s where we get the term knots as a measure of speed for nautical and aviation use.  Today we have GPS to tell us where we are.  However that is based on the position of not stars, but quasars, bright nuclei of distant galaxies, whose motions are currently too small to measure.  Have a happy Thanksgiving.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

 

nasa-map_GPS Quasars

All sky map of quasar locations used as the celestial markers for the GPS system. Chart by David Bobolz, US Naval Observatory.

The chart above is from an article in the Telegraph.

11/24/11 – Ephemeris – The Pilgrim’s voyage

November 24, 2011 Comments off

Thanksgiving Day, Thursday, November 24th.  The sun will rise at 7:50.  It’ll be up for 9 hours and 16 minutes, setting at 5:07.   The moon, 1 day before new, will rise at 8:22 tomorrow morning.

We get the celebration of Thanksgiving from the Pilgrims who celebrated their first harvest, but at the wrong place.  They were originally heading for the mouth of the Hudson River, which was considered North Virginia in back then.  Navigation in those days was rather imprecise.  Latitude was easy to determine at night or at noon but only if it was clear.  Longitude was a guess.  Generally in the age of sail sailors picked a latitude where the winds blew in the right direction to take them to the Americas, then would sail north or south to the latitude they wanted to go.  Storms pushed the Mayflower off course and the Pilgrims ended up near Cape Cod several hundred miles north of their target, an easy mistake to make back then.  Have a happy and safe Thanksgiving.

* Times, as always are for the Traverse City/Interlochen area of Michigan.