The Great American Eclipse is Here!

Illustration credit & copyright: Stephen Mudge.

This is pretty much a repost of the May write up but I want to make sure the information is out there if you haven’t been inundated by it already.  Look all the way to the bottom of this post for all the links you’ll need but if it’s maps you’re looking for, here ya go! https://www.greatamericaneclipse.com/best-places-to-view/

So where’s everyone going to be for the Monday, August 21, 2017 total solar eclipse?  We’re less than a week away now so if you don’t have eye protection, filters for your cameras and telescopes or just plans in general, you’re about as close as you can be to missing out on this one so get Googling.  In the end, if you have nothing to view with you can also look online for local eclipse viewing events near you because I’m sure there will be some and they will have a variety of observation options for you. Actually these group events can be pretty awesome as you can usually find eclipse glasses, white light and hydrogen alpha (H-alpha) telescopes, projection viewing in various forms such as telescope projections, reversed binoculars or equipment like the “Sunspotter” and pinhole projectors in various forms.  You can try to make your own pinhole projectors too: https://www.timeanddate.com/eclipse/box-pinhole-projector.html or https://www.timeanddate.com/eclipse/make-pinhole-projector.html. Have a look around during the eclipse as well, during partial phase, shadows turn into partial eclipses.  From shadows through tree and bush leaves, to interlocked fingers or food strainers/colanders; it’s pretty amazing phenomenon to witness.  Also; I have no idea if this is damaging to your cell phone or not but during every eclipse I see thousands of images that people take with their cell phones during the partial eclipse and although the Sun is still a bright ball of white, the little green/blue lens flare sun still shows up in the image which I guess is pretty cool if you’re willing to risk it.

Illustration credit & copyright: Michael Zeiler.

Where can I see it from?

The 70 mi. (112.6 km) wide path of totality will make landfall in the contiguous United States around Depoe Bay, Oregon (close to Salem, Oregon) at 17:16 UTC (10:16 PDT) and will be seen for about two minutes. It will then travel across the United States in roughly 90 minutes before exiting through McClellanville, South Carolina at about 18:50 UTC (14:50 EDT).

The point of longest duration/greatest eclipse will fall between Carbondale, Illinois to Hopkinsville, Kentucky with each boasting a totality of about 2m 41s which is a great amount of time. Just for fun, the longest totality possible is about seven and a half minutes! Illinois also has the privilege of being the overlap point of the August 21, 2017 and April 8, 2024 total solar eclipses.

If you can’t place yourself under totality, a partial solar eclipse will still be seen for many hundreds of miles to either side of totality so you should still see a pretty good partial eclipse as there will be different gradations visible to you depending on where you’re located.  The closer you are to totality, the greater the partial eclipse will be.  Conversely, the further from totality you are the less partial the eclipse will be until you get further enough away that you won’t see an eclipse at all.  That being said, unless you’re in the U.S. or on a ship or in a plane in the Pacific or Atlantic, the only way you will be able to see this eclipse is after the event, in the images people capture and later in a movie called “Eclipse Megamovie 2017” which should be spectacular. https://eclipsemega.movie/

You will also likely be able to watch the eclipse on a live feed from Slooh https://www.slooh.com or NASA https://eclipse2017.nasa.gov/eclipse-live-stream.

Image credit & copyright: Miloslav Druckmüller, Peter Aniol and Vojtech Rusin.

The Event!

If you’re going to be watching the eclipse in any way this Monday there are some key points to know about before going into this to maximize your experience.  Though totality lasts only about two and a half minutes, the eclipse in its entirety lasts about three hours!  That’s a lot of time under the hot Sun so plan accordingly.

First contact is where it all begins.  This is when the Moon’s disk first touches the Sun’s disk.  When this happens the partial eclipse has begun.  The partial eclipse will grow deeper and deeper, making the Sun more and more crescent until second contact. But wait, there’s more! Just before second contact, and I mean just before as in seconds you can witness a beautiful phenomenon known as the “diamond ring” and then “Baily’s Beads” on the limb about to be eclipsed. The diamond ring formation is when the Moon is just about to cover the last of the Sun’s light.  This remaining light creates a bright point of light at the edge of the black disk which loosely resembles a rather large diamond ring.  Once that’s gone, you may witness Baily’s Beads.  Named after Francis Baily (who first explained the phemomenon); this is the very last thing you can witness before totality.  Just as the Moon is about to fully cover the disk of the Sun you can still see various, random points of light along the limb about to be eclipsed.  This is actually sunlight shining through mountain ranges on the Moon.

Second contact is when totality begins.  This is the only time during the entire phase of the eclipse that you can observe with no eye protection or camera filtering (I just simply wouldn’t risk it with telescopes unless you know exactly what you’re doing).  During totality you may notice some solar prominences around the black disk and this is the only time we can observe the solar corona which some skilled photographers can capture in awe inspiring fashion. During totality you may notice some bright stars and even some planets showing up in the mid-day sky.  The horizon will appear almost twilight-like in every direction, birds will become quiet thinking that its night and it will become noticeably cooler.  Want to do some science?  Get a digital thermometer and record temps before the eclipse, during totality and after the eclipse ends and record the change.

Third contact comes next and this means the end of totality and the return of the partial eclipse just in reverse order from before.  Also; remember the diamond ring and Baily’s Beads that I explained at the tail end of second contact?  Well that entire process repeats itself in reverse order as the very beginning of third contact.  Baily’s Beads will be followed by the diamond ring and then the crescent Sun. That crescent Sun will then grow until fourth contact.

Fourth contact is when the show ends and if you’re still staring at the Sun after this, please stop and find some shade unless you’re making further solar observations.

Approximate location of some nearby planets during totality from Nashville, TN. Where you are will likely look similar but different than this. Made with Stellarium.

What’s a Solar Eclipse?

A solar eclipse (syzygy) is when the Moon passes in front of the Sun, blocking out much of the Sun’s light and these can only happen during new moon. Lunar eclipses are when the Earth gets between the Sun and Moon, preventing much of the Sun’s light from reaching the Moon and these can only happen during full moon phases.  These events can happen because the Moon is 400 times smaller than the Sun but the Sun is 400 times further away thus, they are almost exactly the same size on our sky.

This is all pretty simple as a concept but the details come in varying degrees.  Both solar and lunar eclipses come in total and partial phases with the partials coming in varying degrees.  Solar eclipses also come in what’s known as an annular “Ring of Fire” solar eclipse.  As no orbits are perfectly circular, sometimes bodies like the Moon are closer (perigee) and further away (apogee) from Earth.  When totality occurs during apogee, the Moon looks slightly smaller on the sky than normal so it can’t cover the Sun completely resulting in what appears to be, well; a ring of fire.  There are also hybrid solar eclipses and these are when totality transitions into an annular solar eclipse or vice versa.

As Johannes Kepler discovered a long time ago, orbits are not circular, they’re elliptical or slightly oval.  In the Moon’s case, its average distance (semi-major axis) from Earth is about 238,000 miles (382,900 km) but also during each cycle is has times when it’s closer (perigee) and further (apogee) from Earth. Let’s look at the extremes using 2017 as an example.  The Moon will get as close as 221,958 miles (357,207 km) during perigee on May 26 and it will be as far away as 252,651 miles (406,603 km) during apogee on December 19. That’s a difference of more than 30,693 miles (49,395 km).

Here’s a great animation by NASA Goddard Spaceflight Center’s Ernie Wright

“The Great American Eclipse” Data Links:

NASA YouTube 2017 Eclipse: https://www.youtube.com/watch?v=9C0SeDenPRo

Michael Zeiler’s “Great American Eclipse” page: http://www.greatamericaneclipse.com/best-places-to-view/

Fred Espinak’s “Mr. Eclipse” page for this event: http://eclipsewise.com/solar/SEnews/TSE2017/TSE2017.html

Time and Date page for this event: https://www.timeanddate.com/eclipse/solar/2017-august-21

NASA 2017 Eclipse Page: http://eclipse.gsfc.nasa.gov/SEgoogle/SEgoogle2001/SE2017Aug21Tgoogle.html

NASA 2017 Path of Totality: https://svs.gsfc.nasa.gov/4515

NASA 2017 Eclipse: https://eclipse2017.nasa.gov/

American Astronomical Society (AAS) page for this event: https://eclipse.aas.org/

Dominic Ford’s “In The Sky” page for this event: https://in-the-sky.org/news.php?id=20170821_09_100

U.S. Naval Observatory page for this event: http://aa.usno.navy.mil/data/docs/Eclipse2017.php

Xavier Jubier’s Interactive Map (direct to map): http://xjubier.free.fr/en/site_pages/solar_eclipses/TSE_2017_GoogleMapFull.html

Time and Date: 2017 TSE Hopkinsville, KY: http://www.timeanddate.com/eclipse/in/usa/hopkinsville?iso=20170821

Time and Date: 2017 TSE Boston, MA: http://www.timeanddate.com/eclipse/in/usa/boston?iso=20170821

Bill Kramer’s Eclipse Chasers page: https://www.eclipse-chasers.com/

Photography:

 Fred Espenak “Mr. Eclipse” eclipse photography page: http://www.mreclipse.com/SEphoto/SEphoto.html

Fred Espenak “Mr. Eclipse” eclipse photography settings: http://www.mreclipse.com/SEphoto/image/SE-Exposure1w.GIF

NIKON eclipse photography page with Fred Espenak “Mr. Eclipse”: http://www.nikonusa.com/en/learn-and-explore/a/tips-and-techniques/how-to-photograph-a-solar-eclipse.html

Miloslav Druckmuller solar eclipse corona photography: http://www.zam.fme.vutbr.cz/~druck/eclipse/Ecl2008m/Tse2008_1250_mo1/0-info.htm

Hopkinsville, KY Community College:

Website: http://www.hopkinsville.kctcs.edu/

Facebook: https://www.facebook.com/HopkinsvilleCC

Twitter: https://twitter.com/HopkinsvilleCC

Hopkinsville, KY “Eclipseville”:

Eclipseville page: http://www.eclipseville.com/

Random Hopkinsville places: http://www.courier-journal.com/story/news/2017/07/24/great-american-eclipse-where-see-eclipse-kentucky/495506001/#

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