![]() So to be more accurate, everyone should measure the angular size of their hands and fingers. Everyone has different hands, fingers, and arms.Estimating that path will be easy in the tropics where the path is nearly vertical, and harder in the arctic where it is at a small angle to the horizon, as a small mistake in estimating the angle makes a bigger difference in path length. ![]() And you need to measure along the sun's path, not the height above the horizon. ![]() So if you want to measure the distance the sun will travel until it sets, you have to measure along the right path.Īt 15 degrees per hour the actual speed is more like three fingers in 20 minutes for a typical person, but you could be more accurate by "calibrating" your arm length and finger width. The sun sets when it hits the horizon (and it gets dark when it gets 6, 12 or 18 degrees lower, depending on definition). Unless you are in the tropics at just the right time of year, the sun does not drop directly into the horizon. It will also make a difference if the arm is held out straight ahead, or held to the side and the head turned. This seems a bit high, but might work if the wrist is and elbow are bent, bringing the the finger closer to the eye than in the examples in the references. The image in the question suggests an arms length finger is 15 minutes or 3.7 degrees. Three middle fingers is about 5 degrees, and across a closed fist is about 10 degrees. 1.5cm at one meter is a little over one degree. That rate is 360 degrees per day, 15 degrees per hour, or 3.75 degrees in 15 minutes.Ī typical human has an arm about a meter long, and a pinky finger about 1.5cm wide ( ref, and hopefully you have one you can measure). The earth spins at a constant speed, so the sun moves across the sky at a constant rate. At latitudes and seasons where the sun sets at an acute angle to the horizon, it would take a bit of practise to get it right. ![]() ![]() You have to use your hand to measure the distance the sun has to travel along it's path, not the distance above the horizon. The sun moves approximately one finger width across the sky each 15 minutes, but the sun does not necessarily set vertically down onto the horizon. IN WITNESS WHEREOF, I have hereunto set my hand this twenty-eighth day of September, in the year of our Lord two thousand sixteen, and of the Independence of the United States of America the two hundred and forty-first.This works, but there is one detail missing, and depending on your latitude the picture could be misleading. I also direct that the flag shall be flown at half-staff for the same period at all United States embassies, legations, consular offices, and other facilities abroad, including all military facilities and naval vessels and stations. BY THE PRESIDENT OF THE UNITED STATES OF AMERICAĪs a mark of respect for the memory of Shimon Peres, former President and Prime Minister of Israel, I hereby order, by the authority vested in me by the Constitution and laws of the United States of America, that the flag of the United States shall be flown at half-staff at the White House and on all public buildings and grounds, at all military posts and naval stations, and on all naval vessels of the Federal Government in the District of Columbia and throughout the United States and its Territories and possessions until sunset, on September 30, 2016. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |