by Ken Lund
Question by : How do you calculate the radius of the penumbra during a solar eclipse?
What is the formula to calculate the radius of the penumbra? I'm looking for the pure formula not necessarily in regards to the Earth and the moon.
If it helps, the formula for the length of the umbra can be found here: http://en.wikipedia.org/wiki/Eclipse
Best answer:
Answer by coldfieldgirlYou must know the umbra can fall on Earth's surface, but also it can just not fall on it (it is an annular eclipse then!).
So for your calculation of the penumbra on Earth's surface, the whole distance between Earth and Moon must be taken.
If you suppose:
s = radius Sun
m = radius Moon
N = distance Moon to Sun
D = distance Moon to Earth
then you can do the following:
angle A of one penumbra line = ArcTan ( ( s + m ) / N )
and the radius of the penumbra becomes m + D * Tan ( A )
What do you think? Answer below!
My name is Kurt and I'm back in Stellarium for what will be a regular series on interesting astronomical sights and events you can view each month! In this video we take a quick tour of popular springtime objects, including many galaxies and some early views of summer observing targets. The planets Venus, Mars and Saturn are dominating the night skies and always worth taking a look at. On May 20th at sunset there will be an annular solar eclipse visible from the US, favoring those near the west coast. Information and maps for the May 20th eclipse: en.wikipedia.org Get your solar eclipse glasses and support Astronomers Without Borders here: www.astronomerswithoutborders.org Stellarium is a free open source planetarium software available for Windows, Mac and Linux. It shows a realistic sky, just like what you see with the naked eye, binoculars or a telescope from your location. Get Stellarium for free here: stellarium.org Click 'Like' to let me know if you want me to continue this series in Stellarium, ask questions in the comments and subscribe if you'd keep up with my channel! Background music Kevin MacLeod - incompetech.com
Wednesday, August 1, 2012
How do you calculate the radius of the penumbra during a solar eclipse?
Total solar eclipse today and pregnant women? Myths & rumors.
Question by Chloe'sMommy: Total solar eclipse today and pregnant women? Myths & rumors.
Hey i live in USA, and according to Yahoo! we're going to have a total solar eclipse, I am a very curious pregnant women so i was wondering who all believe in those myths and rumors that a pregnant woment shouldnt step outside her house when the eclipse is happening and close all her windows and shades? And who are the brave souls who are going to watch it??
This is the site where the eclipse was mentioned. http://news.yahoo.com/s/space/20080731/sc_space/solareclipsefridaytofascinatemillions
Best answer:
Answer by rhsaundersNo eclipse will have the slighest effect on any pregnancy.
Give your answer to this question below!
On on end there is an understanding of the solar eclipse being a natural phenomenon. On the other, there is this strong religious belief that calls it a bad omen.
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What Are Black Friday and Cyber Monday and How Can You Make the Most of Them?
by Michael Holden
What Are Black Friday and Cyber Monday and How Can You Make the Most of Them?
Two dates we're excited about this November are Black Friday and Cyber Monday.What are Black Friday and Cyber Monday I hear you cry?Black Friday is the traditional start of the shopping sales in the US. The day follows the American Thanksgiving holiday and is one of the biggest shopping days in the retail calendar. On the Friday, many US retailers open early, often 4am, to launch their sales and take advantage of the increased number of shoppers. This year the date to remember is November 25th.Following the Friday comes Cyber MondayCyber Monday was created by companies to persuade people to shop online and compliment the Friday sales by extending the shopping holiday weekend to Monday. According to Shop.org, who originally coined the phrase, Cyber Monday is now one of the biggest online shopping days of the year. Cyber Monday falls on November 28th this year.But wait there's more!Cyber Black FridayCyber Black Friday (or CBF) was created in 2009 after observers noted that online retailers were launching their holiday sales before Cyber Monday to compete with the Black Friday brick and mortar sales frenzy. According to Talya Schaeffer, founder of CBF, "Cyber Friday sales are typically the largest of the season. Online retailers are hoping that by offering early discounts, consumers will shop early and often".What does it all mean for you?It's a great time to be shopping online. With retail struggling and competition in the bricks and mortar retail sector strong, there should be some big discounts being offered by many US retailers ready to launch the holiday season and with the added incentive of free shipping deals, the weekend of November 25th is the time to be shopping online in the USA.With the downturn in retail sales, and the recession still biting, many retailers may not be waiting until the weekend of November 25 to begin discounting their products. Smart retailers will know that because the US dollar is flat against many international currencies, overseas sales may be the key to recovering their bumper Christmas profits. So the free delivery offers may start early and extend beyond the US borders to international markets for orders above a certain value. This is an attractive offer for many international buyers and shoppers worldwide should be on the lookout for Black Friday and Cyber Monday (and Cyber Friday!) deals as well as free shipping.
Read more on Black Friday deals at as well as the latest deals from American online shopping stores Article Source:
http://EzineArticles.com/?expert=James_Anthony_Harris