Physics and astronomy grad student Nathan Brunetti belongs to McMaster University's Sidewalk Astronomy group, which gives the public free opportunities to see and learn about celestial objects through a powerful telescope.

With a solar eclipse in the offing Monday, Brunetti answered five questions about this rare event.

What are you offering the public on the day of the eclipse and why?

We will have one (specially filtered) telescope, a 10-inch Dobsonian, running and we should have a handful of eclipse glasses to view the eclipse … (and) some really simple pinhole cameras — essentially cardboard boxes with a pinhole poked in the side that will let us look at the sun in a safe way … The pinhole camera will project the image of the sun on a surface we can look at.

You should never look at the sun directly at any time. The only time you can look at the areas of the sun is when there's a total eclipse — which we won't see in this area.

What happens if you look at the sun directly?

You could seriously damage your eye to a severe extent that it causes permanent damage and you could go blind. That's the worst-case scenario, but not impossible … the part of the eye that gets damaged doesn't hurt and doesn't feel pain. You'll only know (it's damaged) later when you can't see … You need special equipment to look at the sun.

Where will Astronomy Sidewalk be on Monday?

We will be set up on the sidewalk by the Engineering Technology Building facing Main Street West from about 11:30 a.m. … It's a pretty good spot for looking at the sky during the day ... People will look in the telescope for about 10 to 15 seconds, and we'll be around to talk to them and answer their questions …

What's the big deal about the eclipse?

It allows scientists to observe the outer atmosphere of the sun, the corona, from the ground, which they can't do at any other time … Scientists are interested in what causes the temperatures in the corona to be different. There are parts that are thousands of degrees, up to parts that are a million degrees, and we're not certain why. It can (also) tell us how light and energy are transported … it can help us understand solar weather and solar winds coming from the sun.

What will Hamiltonians viewing the eclipse safely see?

The eclipse begins around 1:10 p.m. That's when the moon starts covering the sun. At 2:32 p.m., that's when the sun will be covered most by the moon. During that whole time, we'll be looking through the telescope and you'll be able to see the effect right away. (There'll also be a noticeable and impressive effect outside … the sky and area around you will get a little dimmer and still have sharp, dark shadows being cast.)

How to view it:

Aug. 21 Start: 1:10 p.m. Peak: 2:32 p.m. End: 3:49 p.m.

Sidewalk Astronomy will provide safe viewing equipment outside McMaster University Engineering Technology Building.



Safety first: Don't look at the sun directly without special equipment. Regular sunglasses, even very dark ones, or homemade filters offer no protection. The only safe way to look directly at the uneclipsed or partially eclipsed sun is through special-purpose solar filters such as eclipse glasses. The marketplace is being flooded by counterfeit eclipse glasses with some even labelled as if they were ISO-compliant, so be careful. The American Astronomical Society has a list of reputable vendors at eclipse.aas.org/eye-safety. NASA has a list of tips on how to safely use eclipse glasses, and solar filters on telescopes.

More at: eclipse2017.nasa.gov



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