A Partial Eclipse of the Sun Sunday (Safely Observing the Sun)

.....On the afternoon of Sunday, May 20th (which would, I think, be Monday, May 21st in Japan), there will be an annular eclipse of the Sun.  I have not brought this up before because for most of the United States, the Sun will be very low in the sky, if not set.  The Western US might have a shot at it -- Denver will set the eclipse start with the Sun a whopping 15 degrees above the horizon -- and much of Japan will get to see the eclipse at its best.  In any event, I'll mention this here because it is good practice for looking at the Sun, practice that will come in handy at the Transit of Venus next month.

Timing on the Eclipse:
.....For the eastern US, the eclipse will start with the Sun set, or very close to the horizon.  .....From southeast Minnesota, the eclipse starts a mere eight degrees above the horizon at 7:36 PM, and progresses through sunset.
.....From Denver, Colorado, the eclipse starts at 6:41 Pm, and peaks at about 7:20 when the Sun is close (about 8 degrees above the horizon) to setting.  But hey!  It counts as an annular eclipse!  (If you recall all of the big fuss about the "SuperMoon" last month, when the full moon came about when the Moon was at the closest point in its orbit, now, this new moon, is when the Moon is about as far away as it gets, and therefore smaller against the sky, and therefore it cannot fully block out the Sun.
.....If you live in Japan, this will be an annular eclipse peaking around 8:30 in the morning.  You're set.


How To Look At The Sun:


....Most times, the information that you get is simply "Don't look directly at the Sun!" (or, the slightly longer "Don't look directly at the Sun, moron!".  If one does give advice, if the advice is imperfect, or misunderstood, then the people come to you for an explanation.  Well, I'm going to be precise and also tell you at the beginning that if you are going to blame the internet for bad things that happened to you, you are probably already in contact with half a dozen Nigerian Princes, and have enough problems.

Shiny

.....The danger in looking at the Sun is not in the "shiny", but in the type of shiny.  We can treat light as lots of little tiny particles of energy.  Each type of light has a different level of energy; particles ("photons") of red light have less energy per particle than particles of blue light.  The bluer the light, the more energy each particle/photon has, and light that is off the visible charts on the blue end (ultraviolet light, then X-rays, then gamma rays) has more and more energy per photon as you move off the blue end.  The types of light that a glowing object gives off depends on the temperature.  While a hot object gives off all types of light, the hotter the objects the more high-energy photons are part of that deal.  These higher energy photons are dangerous because any given atom or molecule in your body can only interact with *one* of these photons at a time, and the higher the energy of that one, singular, photon, then more likely that might smash up some part of cell doing really important things -- like in your eye, processing light.  A tremendous number of red photons is far less frightening than one UV photon.


.....The Sun is hot.  Really freaking hot.  Even with that, the dangerous (UV) light isn't coming from that part of the Sun.

Not shiny

.....Surrounding the Sun is an atmosphere of much thinner gases.  For reasons that still aren't completely understood, but probably have to do with the Sun's powerful magnetic field, the thin gas above the Sun is at a much, much higher temperature than the surface, so it is this thin gas giving off most of the UV light.  This part of the Sun does give off nearly as much light compared to the surface of the Sun, so the brightness of the Sun causes your eye's iris to shrink down, therefore being smarter than you apparently are -- but much less so during an eclipse.

not pictured: angels

.....Now on to how to not destroy your eyes just to see something cool.  (Although, to be fair, really, REALLY cool.)  You can find plenty of web broadcasts showing the eclipse, transit, whatever, but I'm going to assume that your are at least at little like me, since I'm the only person here while I'm writing this, and assume that part of the appeal is seeing the actual light coming from the Sun at the time that it is happening.  The first, and one of the safest ways of watching an eclipse/transit is by using a pinhole camera.  Take a pin, and punch a hole in a piece of cardboard/stiff paper, and then position another piece of paper beyond the hole.

.....The hole will cause an image of the Sun to appear on the other paper.  This is totally safe, and it will show the progress of an eclipse/transit very well, but details like sunspots will be hard to see.




 .....Shown below is an image of Sun as projected.

Can you see these on the left?

 .....Another thing that can be done is too use binoculars in much the same way.  You may need to use sunglasses due to the brightness of the image, but this is entirely safe to look at.








.....Speaking of sunglasses, do not simply toss on sunglasses and look at the Sun!!! (See: three exclamation points.  On the internet, this means that this is true.)  There do exist products that are safe for looking at the Sun, but they absolutely, positively have to be specifically made for looking at the Sun, and they have to stand behind this.  Simply using dark glass tricks your eye into opening the iris as widely as possible, but it does not protect you against ultraviolet light.  Pictured are some glasses that I found useful; I include them as an example without any particular endorsement.  they have worked well for me, although I get no money if they sell any.  (Although, hey guys, this space for rent!) 

.....I recommend using headwear to protect yourself from the Sun.  Choose something that typically does not get the bright sunlight of success to keep heat off of you.  I'm going with a Brewers cap here for that purpose.  Good luck!  Over the next three weeks, I'll have more and more about the transit.





(All photos not hyperlinked to public domain images are taken by the author, with the last image taken by Anne Marie Leckenby.)