Showing posts with label astronomy. Lunar eclipse. Show all posts
Showing posts with label astronomy. Lunar eclipse. Show all posts

Sunday, February 10, 2008


ASTRONOMY:
LUNAR ECLIPSE COMING FEBRUARY 20:
THE ECLIPSE THAT SAVED COLUMBUS:
As Molly has noted earlier on this blog there is a full lunar eclipse due this coming February 20th. For the times of the phases of the eclipse see our archives for Jan 1, 2008 (also how to convert the times from UT to your own time zone). Last year saw two full lunar eclipses visible from North America. The upcoming one will be the last for some time. For a fuller discussion of all things "eclipsoid" see our archives for the following dates: Jan 22, 2008, Jan 1, 2008, August 28, 27, 26, 24, 20, 18 and 16 in 2007, March 3 and 2, 2007). Lunar eclipses have been prominant in at least a few historical events. Here is one of them...
THE ECLIPSE THAT SAVED COLUMBUS:
The year was 1502, and Columbus had set sail for his fourth voyage to what is now called North America. He sailed with four ships, the Capitana, gallega, Vizcaina and Santiago de Palos. Luck was not with him this time, and the ships began to be disabled due to worms eating through the hulls. After abandoning two of the ships he was forced to beach the final two at St. Anne's Bay on the north shore of Jamaica on June 25, 1503.
The local inhabitants at first welcomed Columbus and his sailors, supplying them with food and shelter. Time, however, dragged on, and after 6 months on the island many of the crew were mutinous, and they took to both robbing and murdering some of the natives. For the natives, on their part the novelty of trading food for tin whistles and other trinkets had worn off. There's only so many whistles that one wants after all. The locals finally decided to cut off the food supply to their increasingly distressful guests. Many of Columbus' crew wanted to proceed to the point of total war to steal what food the locals had. Columbus, however, more rationally calculated that dead natives couldn't keep supplying food in the future once the stolen stocks were used up. So he decided to resort of deception instead.
Columbus carried with him an almanac published by the German mathematician, astronomer and astrologer Johannes Muller von Konigsburg (Latin version Regiomontanus). The astronomical tables contained therein proved to be invaluable for they predicted a lunar eclipse for the evening of February 29, 1504 soon after Moonrise. Columbus arranged for a meeting with the local headman, and informed him that the Christian God was angry with the natives for no longer supplying his crew with food (why he wasn't angry about the theft and murder on the part of the crew is lost to posterity). As a sign of his anger he would obliterate the rising full Moon, making it "inflamed with wrath". Columbus was taking a gamble with the latter threat as not all eclipses produce a reddish colour to the Moon, but it worked out for him. At Moonrise that evening it was obvious that "something was wrong". The lower edge was missing. As the Moon continued to rise the eclipse proceeded, and in the end a dim red ball hung in the sky.
According to Columbus' son Ferdinand the natives soon came running to the beached ships with loads of food, beseaching Columbus to intervene with his God on their behalf. Columbus informed them that he would have to consult with his "god" privately. This "god" was an hourglass that he had in his cabin to time the various stages of the eclipse. After about 50 minutes he came out of the cabin and announced that God was in a forgiving mood and would allow the Moon to gradually reappear. It did, and the locals kept Columbus and his crew well supplied until a relief ship from Spain finally arrived on June 29, 1504. By November 7th Columbus and crew were safely back in Spain. To his extreme good fortune the locals never asked for another demonstration of his power while he was stranded with them. One also has to give him full marks for showmanship. The natives had undoubtedly seen lunar eclipses before, but he still managed to convince them that he could control such events. Thus their acquiesence with his demands. Now, if this audience had demanded an encore..... Such is the nature of belief.

Friday, August 24, 2007


"DOUBLE MOONS" AND "DOUBLE ECLIPSES"; THE REST OF THE STORY":
SECOND LUNAR ECLIPSE OF 2007: DUE AUGUST 28TH:
THE REST OF THE STORY:
As Molly has made plain in a previous post (see'What's All This Double Moon Stuff' earlier today) there will not be either any "double Moon" or "double eclipse" on the upcoming lunar eclipse in the early morning of August 28th. It will be the regular and ordinary lunar eclipse. Yet... is there a "real" "double Moon" or a "double eclipse" ?
The Astroblog site previously mentioned on this blog actually has a photograph of an apparent "double Moon" posted on their site. See http://astroblogger.blogspot.com/2007/07/double-moon.html . This is an optical illusion, but the photograph is "rather attractive" showing the waning(or is it "waxing" because it was taken from the southern hemisphere in Australia ?-more on this later) crescent Moon. Have a look.
There is also a real "double eclipse" referred to as "selenelion" or a "selenehelion" eclipse. This is a rather rare event which can only occur when both the Moon and the Sun are at the horizon when the eclipse occurs. This is also referred to as an "horizontal eclipse". The last time that this occurred was during the lunar eclipse of May 16th over Europe. For this event to occur it has to be either just prior to sunset or just before sunrise. Molly never expects to see such an event in her lifetime, but I really have to look into this. When an "horizontal eclipse" occurs the Sun and Moon visibly eclipse each other as they are rising or setting.
So.. "that's the rest of the story".