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SYFY WIRE Bad Astronomy

BA product review: Celestron's EclipSmart solar viewing binoculars

By Phil Plait

In August of this year there will be a total solar eclipse, the first in many years to cross the continental U.S. I’ll be writing about that soon — oh, yes, I will — but, in the meantime, the optical equipment company Celestron has created two pairs of binoculars for people to use to watch it*.

Part of their EclipSmart line, one is a smaller 10x25 pair ($34.95 on the site) and the other a larger 10x42 pair ($69.95).  

Both binocs are heavily filtered and are safe for viewing the Sun. They’re so dark, in fact, that the Sun is the only thing you can observe with them! The site says they block 99.999% of the visible light entering them (making them an ND 5 filter for you photographers), and also block infrared and ultraviolet light, which is critical for safe solar viewing.

Celestron sent me both pairs to test. I found them both relatively easy to use and of good quality —there are instructions included if you’ve never used binoculars before. No binoculars are just point-and-look; you have to adjust them to match the distance between your eyes, and focus each barrel separately. But don’t worry, it’s not hard, and the instructions given are clear!

They also put together a short video with good instructions on how to use them:

Using them is just like using any ol’ pair of binoculars, except (duh) you have to look at the Sun with them. Nothing else is bright enough to see through them! I have big hands and a big head (har har, spare me the obvious comments, please) so the 10x42 set worked better for me; the smaller 10x25 should be good for folks on the smaller side (and as a bonus are more compact and easier to carry).

The first time I used them, I was surprised to discover it took more than a few seconds to find the Sun. That made me laugh. I mean, c’mon, it’s the Sun! But they’re so dark you get no visual clues on where the Sun is when you look through them. And you have to be VERY careful, because you don’t want to get solar glare into your eyes while looking around (I’ve written about how to safely observe a solar eclipse; note that, in that article, I say don’t use binoculars, but in that case I meant unfiltered ones). Wearing a baseball cap helps. Also (as described in the video), I find what works pretty well to zero in on the target is to first square my body off with it so I’m facing its direction but looking straight ahead, and then putting the binocs up to my face and tilting up.

The view through the solar binoculars is good; the Sun is crisp and clear in both pairs they sent me. For the past few weeks, the Sun hasn’t cooperated much, with no sunspots visible, but then (after many days of clouds and rain here in Colorado) I was able to look at the massive Active Regions 2644 and 2645, a pair of huge sunspot chains across the Sun’s face. They were incredible, and the view was very nice. I could easily make out the individual spots in both chains (NOAA has a nice list of links on what the current Sun’s face looks like if you hope to catch some spots).

Of course, when the eclipse rolls around in August, a pair of binocs like these will be pretty handy to watch it progress. Once totality hits, you won’t want to use them; they’ll block the corona! But for the partial phases, they’ll be nice. And they’ll be fun to use on any sunny day when sunspots are visible.

So, if you want something to use to take a look at the Sun while the Moon is eating it, or when magnetic activity is spotting the solar surface, these would be great. I recommend them.

Celestron also has other equipment like inexpensive solar eyeglasses which are useful for the unmagnified view, as well as a 50mm telescope (which I have not used) and some filters for other ‘scopes, as well.

There are lots of solar observing products out there, but I haven’t tested many yet (except for the Lunt Solar Systems LS 50T H-alpha Sun-observing telescope which I wrote about here). Hopefully I’ll get a chance. This will be my very first total solar eclipse so I want to make sure I’ll be as prepared as possible for it, and have plenty of equipment to choose from.

* I've had a long-standing relationship with Celestron; because I like and respect their brand I contacted them years ago to sponsor my Science Getaways vacation company. They sent me a 20 cm SCT ‘scope which I love, as well as some other equipment which I also like a lot and use pretty often. I’ll be honest, if I didn’t like their stuff I wouldn’t have contacted them in the first place or plug their equipment now! I’m also part of their Team Celestron; an eclectic group of people who use their equipment for astronomy and more earthly observing.

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