Heads-Up! Eclipse Coming!

Seth Jarvis

2012 promises to be a big year, astronomically speaking.  And no, I don’t mean the Mayan calendar and end of the world.

I will write about the eye-popping grouping of Jupiter and Venus that takes place in mid-March in my next blog post.

Today, I want to call your attention on an event that will require a bit of preparation and planning on your part in order to get the maximum enjoyment from it.

On Sunday, May 20th the shadow of the Moon will pass right over the western United States just as sunset approaches.  This will be an “annular” eclipse, meaning that the Moon isn’t quite big enough to completely block the Sun from view.

The Moon's Shadow will arrive in Utah just before sunset on May 20th.

Those of us in the vicinity of Salt Lake City will see the Moon block most of the Sun’s disk, but the Moon will leave a thin crescent of the Sun still shining through. It will seem that the dimming of the sky arrived about an hour ahead of sunset.

Even from Salt Lake City, the eclipse will be quite a sight!

Where you are during this eclipse makes a huge difference in how and when you see it.

The maps below show the path of the eclipse. Between the blue lines observers will see the Moon fully within a bright circle of sunlight, though the Moon will not be exactly centered within the ring.  Outside of but near the blue lines observers will see a partial eclipse. The closer you are to the band marked by the blue lines, the more the Sun will be eclipsed by the Moon.

Observers located along the red line will see the Moon exactly centered against a ring of sunlight.

Cedar City, Utah is just a whisker off the center line. The view should be spectacular!

I plan to be in the vicinity of Kanarraville, Utah, about 20 minutes south of Cedar City on Interstate 15 on May 20th.  Even though Cedar City would be a grand place to observe the eclipse – I’m being picky and aiming for dead-center in the eclipse path.

(UPDATE: I’m not going to be in Southern Utah – I will be at the Dimple Dell Recreation Center in Sandy (106th So. & 10th E.) with solar telescopes, pinhole projectors and #14 welder’s glass. 6PM Sunday!  See you there!)  

Trust me, you want to see this.  There won’t be another partial solar eclipse visible from Utah until August of 2017, and there won’t be another Annular Eclipse visible from Utah until October of 2023.


So you’ve decided you want to observe this.  You’ve packed up the car and are headed for somewhere in between the blue lines.  How do you plan to look at the eclipse?  Just look up?  NO!  You’ll do permanent, serious damage to your eyes if you look into the Sun.

You need proper filters. 

Doubling-up on sunglasses will not provide sufficient protection. 

Loading a piece of glass up with soot from a candle flame runs a strong risk of either making the glass too dark to see anything, or letting damaging amounts of light through to your eyes.

Holding two pair of polarized sunglasses crossways from each other will not protect your eyes. 

I’m not even going to comment on the old trick of using exposed black & white film negatives because 1) who in the world has b&w film anymore? 2) few people know how to properly develop the film into safe sun filters.

I recommend against trying to use welder’s goggles unless they are rated for arc-welding (at least grade 14).

No, to do this right you need to get yourself a Sun filter that is specifically made for safe observing of the Sun.  They can range from inexpensive cardboard glasses that cost maybe a couple of bucks, to fancy filters that fit snugly over the openings of your binoculars or telescope.  They can set you back the better part of a hundred dollars, but aren’t your eyes worth it?

What I really recommend you do is watch the Clark Planetarium blog page and follow us on either Facebook or Twitter for announcements of where you can go in Utah to look at the eclipse through telescopes that have been fitted with proper solar filters.  You’ll get a grand view, safely, and you’ll be in the company of other knowledgeable folks who’d love nothing more than sharing information about this rare event with you.

I’m posting this now because if you’re going to try to set out on your own to observe the eclipse (or the Transit of Venus on June 5) you’re going to have to get started now to track down and acquire proper solar filters for your bare-nekkid eyes, your binoculars, or your telescope. 

If you wait until the week before the eclipse you may have a very difficult time finding any, so it’s not too soon to start looking.

Stay tuned!

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10 thoughts on “Heads-Up! Eclipse Coming!

  1. Hi Sue,

    Short answer: Yes.

    Long answer: We carry both the personal cardboard sun filters that you wear like the disposable sunglasses you get after a visit to an eye doctor, as well as solar filters to fit an assortment of popular telescopes. That said, you can also find many types of solar filters by shopping online. The main point I want to make is that if you plan to observe the eclipse on May 20th or the Venus Transit on June 5th, you shouldn’t dawdle to make arrangements for eye protection. These things will likely become scarce by May.

  2. I’m confused along with several of my friends abt the DATE that the annual eclipse will occure. NASA says the 20th of may but are they not talking UTC? If so then subtracting 6 hrs from 20th May at 1:30 would be 7:30pm on the 19th of may. Should I change my hotel reservations in St George?

  3. Terry, as seen from southern Utah, the annular eclipse takes place during the late afternoon of Sunday, May 20th. From locations in the vicinity of St. George and Cedar City the eclipse begins around 6:30 PM MDT, reaches maximum roughly an hour later, and ends just as the Sun is setting.

  4. I’m confused by your answer concerning solar filters for viewing the solar eclipse. In your response you say you (Clark?) does sell them but then said similar one can get them from one’s eye doctor. Are these from one’s eye doctor the glasses they give you after dialating your eyes? If not can you fill me in on how to purchase them from you? Also, what about taking digital pnotos of the eclipse. Do I need a filter for my camera?

  5. John,

    The only thing that real eclipse-viewing glasses will have in common with the dark glasses you get from an appointment with your eye doctor is that they both have cardboard frames. I apologize if I gave the impression that you can use the dark glasses you get after an eye exam for the eclipse. YOU SHOULD _NOT_ DO THAT.

    An important point worth repeating is this: Use _only_ viewing equipment that has been _specifically_ designed for looking at the Sun.

    Yes, we sell those cardboard-framed eclipse glasses here in our store for about $2. You can also find them online by doing a google search for “eclipse glasses.” Just make sure the glasses you buy are specifically made for eclipse viewing.

    In terms of digital photography, I will need some kind of strong filter. The CCD chips used in digital cameras will be overwhelmed by raw sunlight and you won’t get any kind of useable image.

    Here’s a web site that might help: http://www.mreclipse.com/SEphoto/SEphoto.html

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  8. Along the wasatch front, would it be beneficial at all to be on a mountaintop, instead of on the valley floor?

  9. Steve, the weather forcast for northern Utah is good for Sunday, so the only reason to consider a higher altitude location is to achieve a flatter western horizon. When the eclipse ends (~8:30 PM MDT) the Sun will be about ten minutes away from setting, so it will be practically on the horizon. The extra few degrees of visibility you might get by being higher up might be beneficial. That said, I think the last 20 minutes of the eclipse will be anticlimactic for most folks, and so a perfectly flat western horizon isn’t going to be a big issue for them.

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