EDITOR’S NOTE: With one week until the solar eclipse, West Seattle’s best-known sky-watcher is continuing to offer helpful info – in this report, the basics about the eclipse and safely watching it. Still to come, a list of where to eclipse-watch in West Seattle!
By Alice Enevoldsen
Special to West Seattle Blog
Are you ready for the big solar eclipse that’s now one week away, on August 21?
No?
Don’t worry, I’ve got your back.
QUICK FACTS
Date:
Monday, August 21, 2017
Times:
Start of partial eclipse: 9:08 am
Maximum eclipse: 10:20 am — Coverage of the Sun: 92%
End of partial eclipse: 11:56 am
Visible from West Seattle? Yes … but read on for caveats
Special Equipment Needed? Yes: safe observing glasses or a pinhole viewer. (Here’s where to look and, in the comment section, where WSB readers are finding them.) Read on!
VIEWING FROM WEST SEATTLE
This event will be visible from West Seattle (and all of Seattle), but from here it will be a partial eclipse. It will not get dark. This is why I and a million — I mean that literally — other people are planning to drive to Oregon to see the total eclipse.
During the eclipse, the Moon will cover 92% of the Sun as seen from West Seattle. For comparison, the annular eclipse of 2012 had the Moon covering 94% of the Sun if you were in the path of the umbra, the darkest part of the shadow. I was in California in the umbra during that eclipse, and it got noticeably less bright outside, like a cloudy day, and a lot cooler suddenly. I predict similar effects in Seattle: not total darkness.
This shows approximately how much of the Sun will show behind the Moon when the Moon covers 90% of the Sun.
Where should you look to see this event? At the Sun, which brings me to my next section:
SOLAR ECLIPSE VIEWING SAFETY
You absolutely need special equipment to see this event safely. Luckily the special equipment isn’t spendy, and some can be made at home.
Option 1: Eclipse Glasses
Eclipse glasses are also called solar observing glasses and they are not related to sunglasses. There are only a handful of companies that make glasses that meet the current international standard of safety. Luckily, those companies make most of the glasses that are sold.
There has been a scare about fakes being sold online, many through conglomerate vendors like Amazon. This does NOT mean that all glasses purchased through Amazon are fakes. Amazon hosts individual vendors, and many of those vendors are entirely reputable. The list maintained by the American Astronomical Society includes the names of several sub-vendors within Amazon that are safe.
To use glasses safely:
Check that they are marked compliant with the safety standard ISO 12312-2:2015
Check that the lenses are flat and free from scratches, punctures, or damage. Discard them if there are problems.
Stand still, looking away from the Sun.
Put on the glasses.
Look toward the Sun.
If the Sun looks bright, or your eyes get tired from the glare, then the filter is letting too much light though. Look away and use a different filter.
When finished viewing:
Turn away from the Sun.
Remove the glasses.
(Again, here’s updated availability information from eclipse-glasses-shopping WSB readers.)
Children must be supervised when viewing the Sun using any method. That said, even children as young as 2½ or 3 can safely use eclipse glasses with a little help. You do not need a different size of glasses for children, but you will need to modify them. To keep the glasses positioned correctly, punch holes in the back of the temples of the glasses, behind the ears. Attach a string, elastic (a cut hairband works well), or a pipe cleaner to both ends while your child is wearing the glasses.
(Eclipse glasses modified for young children)
(Kids demonstrating the correct usage of “adult-sized” solar viewing glasses)
Option 2: Pinhole Projection
The second method I will mention is called pinhole projection. You already have, in your hands, all the tools you need to do this method.
Rule #1 of pinhole projection: NEVER look at the Sun.
Turn your back to the Sun and look at your shadow.
Next make a “pinhole,” or several: if you cross the fingers of one hand over the fingers of the other you make a waffle pattern. Keep your fingers spaced far enough apart to make visible holes between them.
You can also use a colander/spaghetti strainer or something similar.
Look at the shadow of your hands on the ground, or perhaps something smoother like a piece of paper. Every space between your fingers will cast an image of the eclipsed Sun on the ground.
You’ll find yourself “holding” half a dozen eclipses!
(Using a colander to project an array of images of the Sun on the flat surface of an open umbrella)
There are ways to improve this, of course, such as building a simple pinhole projector. Find the longest box you can, width doesn’t matter, and cut two holes: one in one flat end and one “window” on the side of the far end. Cover the first end with aluminum foil and poke one tiny hole in it with a pushpin. Place white paper inside the far end. There are detailed instructions all over the internet, just don’t look through the pinhole.
To use your pinhole projector:
Don’t forget Rule #1! NEVER look at the Sun!
Turn your back on the Sun, and hold your projector so the pinhole points behind you.
Watch the “far” end of your projector and tilt it around until the shadow of your projector on the ground is as small as possible.
Once the shadow looks just like the shape of the end of your box, look inside your window, down at the white paper: away from the Sun.
Keep moving the projector slightly up and down or side to side until you see a small bright dot shine on the white paper. If your projector is 4½ feet long, like mine, the dot will be about the size of the tip of your pinky finger, but it is an image of the Sun!
(Viewing a projected image of the Sun using a pinhole projector)
SAFETY DURING THE ECLIPSE
Please remember that it is the peak of August, and use appropriate heat and Sun-exposure precautions when viewing the eclipse.
*Drink plenty of water
*Wear sunscreen or sun-protective clothing
*Watch for signs of heat-exhaustion
If you are travelling to Oregon for the eclipse, be aware that the Office of Emergency Management is expecting significantly more visitors than usual to the area.
*Be prepared for traffic jams as if entering or exiting an area in a state of emergency.
*Be prepared to stay hours or even a day longer than you planned.
*Be prepared for significant heat, wildfires, and long waits anywhere that provides services.
Resources:
NASA Eclipse 2017
Interactive Google Map #1*
Interactive Google Map #2 (works better on phones than #1)
American Astronomical Society Eclipse 2017
Mr. Eclipse
Stellarium: free planetarium software for your home computer, or Android device. Bring up the sky for anywhere in the world, any time and date in history or the future.
Clear Sky Chart: the astronomer’s forecast for the next couple days. Cloudcover, darkness, and “seeing” which is how nice it is to view the stars, all on one handy chart.
USNO: dates and times of astronomical happenings.
International Dark Sky Association: how to help your neighbors enjoy the night sky.
Who is Alice?
Although she is an astronomy instructor for South Seattle College and a volunteer with NASA’s Solar System Ambassadors program, the suggestions and opinions put forth in this article are Alice’s own and not those of any of those organizations. You can find more about astronomy from Alice at alicesastroinfo.com or on Twitter as @AlicesAstroInfo and Facebook.
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