Total Solar Eclipse of August 21, 2017
On August 21, 2017, a Total Solar Eclipse will occur along a 114 km wide track running across the Continental USA from Salem, Oregon to Charleston, South Carolina. At most points along the track, totality will last more than two minutes, peaking at 2 minutes, 41.6 seconds just east of St. Louis, Missouri. Observers south and north of the track will see only a partial eclipse, the amount of sun covered varies depending on the distance north or south. Basically, northern South America and all of Central and North America will be treated to at least part of the eclipse.
The time of totality, and the height of the Sun in the sky, depends on your longitude. The western states and provinces will see maximum eclipse around 10:18 am local time, and the Sun will be nicely positioned 40 degrees above the eastern horizon. In central Missouri, maximum eclipse occurs at 1:14 pm local time, with the Sun 63 degrees above the southern horizon. The eastern seaboard will see totality around 2:48 pm local time, with the Sun 61 degrees above the southwestern horizon. In each case, first contact occurs about 90 minutes earlier and last contact takes place 90 minutes later.
Totality brings additional observing opportunities, but you’ll need to work quickly. The naked eye star Regulus, in Leo (the Lion), will be sitting less than one degree (about a finger’s width) to the upper left of the eclipsed Sun. Reddish Mars, though slightly dimmer at magnitude 1.77, will be 8 degrees (just under a fist diameter) to the right of the eclipse. Looking farther along the same line, very bright Venus will be located 34 degrees to the lower right (west) of the eclipse. Look 51 degrees in the opposite direction for bright Jupiter. For a challenge, you can hunt for Mercury, at visual magnitude 4.2, sitting only 10 degrees to the left of the eclipse. You can also look for a 360° sunset all around you — and the diamond ring and Baily’s Beads effects caused by sunlight sneaking past the moon’s uneven limb.
While a partial eclipse shape can be seen through thin cloud, clear skies are extremely important for enjoying totality during a solar eclipse. Be sure to check your local forecast the days and hours ahead, and be prepared to drive east or west along the track of totality to reach clear skies. Ensure that you don’t veer too far south or north.
Here are youtube instructions for Star Walk 2 app:
and Solar Walk 2 app how to do it:
Observing the Solar Eclipse
It is NEVER safe to look at a Solar Eclipse without eye protection, with one exception. Observers during the few minutes of totality may turn their gaze upon the Moon-obscured Sun and see the glorious corona and red solar prominences that rise from the Sun’s photosphere. Outside of totality, part of the Sun’s disk is always exposed, and any amount of unprotected viewing is harmful to your eyes. Sunglasses are NOT enough to protect your eyes. They may make the sunlight dim enough to seem comfortable, but they do not filter out the harmful invisible ultraviolet (UV) and infrared (IR) radiation that damages eye tissue. Your retinas do not have pain receptors that will alert you to the damage you’re doing to them.
Safe methods of observing solar eclipses include special eclipse glasses (commonly inserted into astronomy magazines published prior to major eclipses), #14 or darker welder’s glass, pinhole projection setups, and special telescope filters. NEVER pass unfiltered sunlight through a telescope or binoculars. Damage to vision will be instantaneous, the equipment will likely suffer damage, and there is risk of fire, too.
Via Chris Vaughan.