Test your eyes with a star

(Photo by William Creswell)

It seems that everyone is aware that the name of this year is also the term for sharp vision: 2020. Happily, the night’s very best eye test is available at nightfall right now, in early January. Go out at 5:30 any evening and look just slightly to the right of where the Sun set, until you see the brightest star. This is Vega, and it’s only about one-third of the way up the sky from the northwestern horizon. It’s not high up.

If you have binoculars, bring them along and point them to Vega. That instrument will easily bring out its bluish color, and will also show you a much dimmer star directly above Vega. This is Epsilon, the focus of this week’s column.

Through the binoculars, Epsilon will stand out as a beautiful double star. The question is whether you can see it as a double with just your naked eye – for this is the very finest test of vision in all the heavens.

I’ve been asking groups of people if they can see Epsilon as a double for a full half-century now. What I found is that only perhaps one adult in 50 can split it as a double star. But with groups of kids and teenagers, it’s more like one in every eight or ten can detect it.

It’s a tough test, because normal 20/20 vision will not quite split Epsilon. You need to have slightly better-than-normal vision – specifically, 20/15 vision. People with that degree of keen eyesight can read the ninth line in the standard Snellen eye chart. Does this include you?

Find out the next clear night. Again, simply look at the direction of sunset at 5:30 p.m. The brightest star just to the right of where the Sun set is Vega. The little star just above Vega is Epsilon. If you can see it as two little stars side-by-side, almost touching each other, then this year of 2020 has your name on it.

Want to know more? To read Bob’s previous columns, click here. Check out Bob’s podcast, Astounding Universe, co-hosted by Pulse of the Planet’s Jim Metzner.