The corona of the Sun is not usually visible to the naked eye; even though it is fairly bright, the Sun itself is so MUCH brighter that you cannot see it. Except during a solar eclipse, when the Moon blocks the direct rays of the Sun.
But astronomers can see the Sun's corona at any time,by using an instrument called a coronagraph; this device blocks the direct rays and allows astronomers to study the corona. Think of it as an artificial eclipse maker.
Sometimes, during a total solar eclipse, the corona of sun is visible to our eyes.
CORONACORONA
chromosphere
corona
No single eclipse ... solar or lunar ... is ever visible from every place on earth.No single solar eclipse is ever visible from every place or even half of the earth.
There were partial solar eclipses visible from Phoenix including a 71% eclipse on April 7, 1940. There were no total solar eclipses visible in Phoenix during the 1940's.
The Umbra
The last total solar eclipse visible in Pittsburgh occurred on August 21, 2017. During this event, the city experienced a partial eclipse, with about 80% of the sun obscured. The next total solar eclipse that will be visible from parts of the United States will occur on April 8, 2024, but Pittsburgh will only experience a partial eclipse then.
The corona.
The outermost layer of the sun, corona, is visible during a total solar eclipse.
The ring visible as the moon passes in front of the sun during a solar eclipse is called the corona. This appears durian a total solar eclipse, when the apparent size of the moon is larger than the sun.During an annular eclipse, where the moon's apparent size is smaller than the sun, the ring visible around the moon is called the annulus.
If there is a total lunar eclipse, everybody sees it as total. If there is a total solar eclipse, only people in a small part of Earth see it as total - most will see it as a partial eclipse, or not at all.