Solar Eclipse - August 21, 2017
First Contact
20%
40%
60%
80%
Diamond Ring
Baily’s Beads
Maximum Eclipse
Baily’s Beads
Diamond Ring
80%
60%
40%
20%
Fourth Contact
The above grid shows the sequence of events for this eclipse. The event timings for this eclipse were: First Contact - 10:24 AM, Second Contact - 11:45 AM, Maximum Eclipse - 11:46 AM, Third Contact - 11:47 AM, and Fourth Contact - 1:12 PM (MDT). Totality lasted for 2 minutes 29 seconds.
Definitions:
First Contact - During a solar eclipse, the moment the Moon makes contact with the sun; this marks the beginning of the eclipse.
Second Contact - During a solar eclipse, the moment the Moon covers 100 percent of the sun's disk; the instant totality begins.
Totality - During a solar eclipse, the length of time between second and third contact; any instant the Moon covers 100 percent of the Sun's disk.
Third Contact - During a solar eclipse, the instant totality ends.
Fourth Contact - During a solar eclipse, the moment that the disk of the Moon breaks contact with the sun; this moment the end of the eclipse.
Baily’s Beads - The effect often seen just before and just after totality when only a few points of sunlight are visible at the edge of the Moon, caused by the irregularity of the lunar surface; named after English astronomer Francis Baily, who first explained it in 1836.
Corona - The shell of thin gas that extends out some distance from the Sun's surface, normally visible only during totality; corona is the Latin word for "crown."
Diamond Ring - The effect just prior to or just after totality of a solar eclipse when a small portion of the Sun's disk plus its corona produce an effect similar to the real-world object it's named after.
(Definitions Source - Astronomy Magazine)
Sunspots
Two groups of sunspots were seen on the solar surface on the day of the eclipse; AR2671 and AR2672.
Sunspot - A temporarily cooler (and therefore darker) region on the Sun's visible disk caused by variations in its magnetic field.
(Definition Source - Astronomy Magazine)
Diamond Ring
Baily’s Beads
Prominences
A number of prominences were seen on the solar limb during the eclipse. Two are shown here.
Prominence - A large scale, gaseous formation above the surface of the Sun, usually occurring over regions of solar activity such as sunspot groups; during totality, observers often see prominences seeming to erupt from the dark edge of the Moon.
(Definition Source - Astronomy Magazine)
Maximum Eclipse
This image is a composite of exposures centered around 11:46 AM; maximum eclipse.