Great American Solar Eclipse

On August 21, 2017, the Moon will pass between the Sun and the Earth, casting its shadow across the continental United States.
This will be the first total solar eclipse to pass over the ‘lower 48’ in 38 years. The last one was February 26, 1979 and crossed over only 5 states. [1]
This time, 14 states will see a total solar eclipse and everyone in the contiguous United States will see at least a partial solar eclipse. [2]

Join us at Ben May Main Library in Bernhiem Hall to watch the live stream from NASA.
Monday, August 21st, 11 a.m. - 3 p.m.

How Can You See It?


“The result is a loss of visual function, which may be either temporary or permanent depending on the severity of the damage…injuries occur without any feeling of pain (the retina has no pain receptors), and the visual effects do not become apparent for at least several hours after the damage is done (Pitts 1993).” [3]

Use a pair of ISO 12312-2 compliant eclipse glasses to watch the eclipse directly.
Do not use your sun glasses to view the eclipse.
MPL has distributed all of the glasses the library has puchased.

If you do not have a pair of eclipse glasses, the other way to safely watch is using indirect methods like projection.

Quick and easy projection:

  1. Get a piece of cardboard or thick paper
  2. Cut a one-inch hole in the center
  3. Tape a piece of foil over the hole
  4. Make a pinhole in the middle of the foil
  5. Stand with the sun behind you and aim the light coming from the hole at a piece of white paper or a white surface
  6. The farther the projector is from the surface, the larger the image will be.

What is it?

A Special New Moon

Solar eclipses can only happen when the moon is in its New Moon phase: when the alignment of the Sun, the Moon, and Earth leaves the side of the Moon facing Earth in complete darkness. But eclipses don’t happen every New Moon, as the Moon’s orbit is tilted causing its shadow to miss the Earth about five out of six times. [4]

Umbra vs. Penumbra

“The Moon's shadow can be divided into areas called the umbra and the penumbra. Within the penumbra, the Sun is only partially blocked, and observers experience a partial eclipse. The much smaller umbra lies at the very center of the shadow cone, and anyone there sees the Moon entirely cover the Sun in a total solar eclipse.” [5]

What will Mobile see?

Mobile, AL will be within the shadow’s penumbra - 81% of the Sun will be obscured by the Moon. [6]

When will it start?

The Eclipse will begin at 12:01 p.m. and end at 3 p.m., lasting about 3 hrs. Maximum eclipse is at 1:33 p.m. [6]

How does it work?

Check out these great, to scale, illustrations of the Moon’s tiny shadow moving over the Earth!


  1. Bakich, ME 2015, 'First look at the 2017 total eclipse: excitement is building for the first total solar eclipse in the U.S. in 26 years', Astronomy, 6, p. 54, Academic OneFile, EBSCOhost, viewed 8 August 2017.
  2. "Eclipse: Who? What? Where? When? and How?", NASA. Retrieved 8 August 2017. Viewed 8 August 2017.
  3. Chou, B. Ralph "Eye Safety and Solar Eclipses", Annular and Total Solar Eclipses of 2010, NASA/TP—2008–214171, 4.1, p.64.
  4. "2017 Eclipse and the Moon's Orbit", NASA. Scientific Visualization Studio. Retrieved 8 August 2017
  5. "2017 Total Solar Eclipse in the U.S.", NASA. Scientific Visualization Studio. Retrieved 8 August 2017
  6. "Solar Eclipse of 2017 Aug. 21 for Mobile, Alabama", U.S. Naval Observatory Astronomical Applications Department. Solar Eclipse Computer. Retrieved 8 August 2017