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.
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.
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.
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.
DANGER DANGER DANGER!!!
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.