Solar eclipse of August 21, 2017
The total solar eclipse of 21 August 2017, the umbra is the North American continent west to sweep from the east coast of the United States. The last to be seen on the U.S. mainland total solar eclipse is then returned 38 years. The eclipse begins in the Pacific and ends in the Atlantic Ocean, outside the American continent meets the umbra not on land. On his way from the northwest to the southeast coast of the United States, the umbra sweeps over a total of 14 U.S. states: Oregon, Idaho, Wyoming, Nebraska, Kansas, Missouri, Illinois, Kentucky, Tennessee, Georgia, North and South Carolina and Montana and Iowa, the latter two are striped but only slightly from the umbra.
The partial phase of the eclipse can be observed from all of North America and Greenland, also from Central America and northern South America. On the west of Africa and Europe, a slight covering can be seen by the moon during sunset in ideal conditions at the end of darkness.
The solar eclipse of August 21, 2017 in the Saros cycle 145 of 11 August 1999, the zone of totality Central Europe crossed the successor of the last eclipse of the 20th century. The maximum duration of totality is 2 minutes and 40 seconds longer than the eclipse of 1999.
Course
About 1500 kilometers south of the Aleutian Islands of the umbra of the moon in the Pacific at 16:50 UT (Universal Time ) meets for the first time the earth's surface. During the umbra sweeps the nearly 3900 km in about 27 minutes to the West Coast of the United States across the Pacific, grows the width of the shadow corridor, where the darkness is totally seen, from an initial 62 to 100 kilometers. The first U.S. city that is made by the umbra, Newport is in the state of Oregon. There, the duration of totality is already 1 minute and 44 seconds. A little later reaches the umbra Salem, the capital of the state. From 10:17 local time, the nearly 40 ° above the horizon standing morning sun is covered there for just two minutes from the moon. Then crosses the umbra Idaho, where the cities Stanley and Rexburg are close to the central line. Next, the darkness reaches the state of Wyoming and the totality zone extends there through the middle of the Grand Teton National Park, Yellowstone National Park is located a bit too far north. A little later, the umbra crosses the Wind River Range and the highest peak, the Gannett Peak, which at 4209 meters is the highest point in this darkness, which is taken from the umbra. From Casper the umbra follows the course of the North Platte River and reached the state of Nebraska. In the zone of totality is there also the Chimney Rock, a prominent landmark for settlers who moved to the Oregon Trail to the west.
In Nebraska, the shadow zone leaves the mountainous regions of the Rocky Mountains and crosses the Great Plains. First, from North Platte, follows the path of shadow 400 km of Interstate 80 to Lincoln, the capital of the state, which lies at the northern edge of the zone of totality. Little upriver from St. Joseph the umbra reaches the Missouri and follows him almost to its confluence with the Mississippi at St. Louis. The metropolitan Kansas City is located on the southern, St. Louis at the northern edge of the zone of totality, of the two cities connecting, running from west to east section of Interstate 40 consequently leads through the shadow zone. On his way from Nebraska to Missouri the shadow corridor still roams the northeast of the state of Kansas and a tiny corner of southwestern Iowa. The umbra then crossed the Mississippi and reached Illinois. Near the central line is Carbondale, where the moon eclipsed the sun for 2 minutes and 38 seconds. Less than seven years later, on April 8, 2024, this city will experience an even longer totality of over four minutes because of running from southwest to northeast shadow path of the eclipse of 2024 crossed here the shadow path of the 2017er - darkness and Carbondale is 2024 even still closer to the central line.
After Southern Illinois the umbra reaches the western Kentucky, where the darkness reaches its maximum. Little northwest of Hopkinsville stops on the central line at the total eclipse of the sun from 13:24 local time for 2 minutes and 40 seconds. The width of the core shadow zone here is 115 km, the sun is 64 ° above the horizon. Next southeast of the umbra in Tennessee reached the South, Nashville is located in the core shadow zone and experiencing a totality of 1 minute and 55 seconds. Then the umbra crosses the southern part of the Appalachian Mountains, Great Smoky Mountains National Park is located in the zone of totality. The point where Georgia, North and South Carolina abut, is located near the center line, so that in all three states of the total solar eclipse can be observed, however, the visibility is limited with the exception of South Carolina to a small area. Columbia in South Carolina is to Salem, Lincoln, Jefferson City and Nashville, the fifth capital in the totality zone and reaches 2 minutes and 30 seconds the longest totality duration.
At 14:49 local time leaves the umbra at the Cape Romain National Wildlife Refuge on the southeast coast of South Carolina in the Americas. On its further way across the Atlantic the umbra is no longer true on land, the Bermuda Islands lie 800 km too far north, the Bahamas about the same distance to the far south. Near the equator, about 300 kilometers south-west of the African coast, the umbra loose during the sunset from the earth.
Weather outlook
Overall, the weather prospects are in the zone of totality of the North American continent in late August pretty cheap: The summer storm season subsides and the often bad weather -making polar jet stream has not yet moved from Canada to the south. Just off the west coast of Oregon the conditions are not favorable because of the frequent rains out the moisture of the westerly winds in the Cascade Range there. But already in the Willamette Valley east of this mountain reign with a cloud probability of less than 35% very good conditions. Further east in the Rocky Mountains, the prospects are cloudy with some probabilities over 50 % again significantly less favorable, with the valleys, such as the Snake River, remain favored. The lowest cloud probability of the entire zone of totality there is west of North Platte, Nebraska, it is there little more than 30%. Hardly less favorable are the conditions on the border between Kentucky and Tennessee, where the darkness reaches its maximum. To the east of the Tennessee landscape rougher and the cloud probability in the other shadow corridor is greater, in the Appalachian Mountains it is 50 %. In the lower elevations on the southeast coast of South Carolina, finally, the conditions are favorable again by 7-8 %.
Planned research projects
A project was initiated to intensify by observing the eclipses of the 2020s the study of the physical properties of the solar corona, where the darkness is to play a key role in August 2017. Enable Advances in image processing and the technical improvements of the detectors in recent years to use the available diagnostic tools in the near infrared and visible range of light. The investigation of the emission lines of these wavelength ranges has several advantages, among others, that the excitation process, the proportion of radiation excitation over that of the collisional excitation is relatively high compared to the ultraviolet range.
A research group led by Hugh S. Hudson asks their " Mega Movie " project to help the amateur photographer to put together a film can, showing the eclipsed sun during the one and a half hours, which will require the umbra to cross the American continent. This is expected to new insights into the solar corona, which can be through the darkness pictures taken from a location not win - although these high quality recordings are limited to the duration of totality in one place. Compared to the recordings of the current located in space coronagraph to promise the researchers faster image sequences and images with higher resolution as well as information on areas of the corona, which can not cover this coronagraph.
The joining of the recordings of different origin and quality requires special procedures in the calibration, it is to be expected with incomplete or erroneous position information and image information. The software used for calibration enables the way to repeat 1919 experiment carried out to test the general theory of relativity using today's digital cameras, Eddington during the solar eclipse. Although current radio-astronomical methods are far more accurate and, therefore, such an experiment has little scientific value, but it is hoped to be able to motivate with the handwritten test of Einstein's theory many Amateuerfotografen, to participate in the mega movie project. The constellation for examination of the light deflection of starlight by the gravitational force of the sun is low in the 2017er - darkness, for Regulus, the main star of the lion, and a star of the first magnitude, only about one degree is east of the eclipsed sun. Its apparent position would have to move by 0.74 arcseconds over its actual position during the Maximus of darkness.
The following eclipses
The next four following this darkness eclipses are all purely partial. In 2018, in which there is no central eclipse, partial solar eclipses to occur on 15 February, 13 July and 11 August. The latter eclipse is visible from northern Europe. In 2019, it comes on January 6 again to a partial eclipse before July 2, 2019 about 22 months after the eclipse of August 2017, only again followed by a total solar eclipse.
The shadow axis of the moon's shadow will meet in the next ten years two more times the United States: First, at the annular eclipse of 14 October 2023 moon shadows on a very similar place as 2017 meet in Oregon from the west to the North American continent, the shadow path then runs over 2017 more south to Texas. Less than six months after this darkness sweeps over the umbra of the moon on April 8, 2024 from Texas to Maine again the United States.