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The doors of perception: there's a way your telescope does better than the Hubble.

If the doors of perception were cleansed every thing would appear to man as it is, Infinite. For man has closed himself up, till he sees all things thro' narrow chinks of his cavern.

--William Blake, The Marriage of Heaven and Hell (1793)

The eye is a narrow chink indeed through which we perceive the cosmos; your pupil in the dark opens to no more than about 7 millimeters wide. A telescope enlarges its width only to several inches.

Moreover, your eye sees only a narrow slice of the electromagnetic spectrum: all the forms of "light." How much richer would the world be if we saw it in the full spectrum, from radio to infrared to ultraviolet to X-rays to gamma rays?

Machines do it (though not all at once), and modern astronomy is built on them. But for perceiving what the machines serve up, we're still back to that 7-millimeter chink.

Our senses evolved for exactly one purpose: to make a model of our local reality just good enough for us to survive and thrive in. So did the senses of an angleworm. That being the case, your natural vision under a dark sky is probably the closest you can come to cosmic reality, at least for interpreting it in ways that mesh properly with the rest of your world.

Your view in binoculars or a telescope also counts, because that's simply what you would see if you could move closer to each object for a better look.

Remember this the next time you're struggling to detect some dim galaxy or nebula and wishing you could see it "the way it really is," the way you remember its Hubble Space Telescope pictures. You can browse hundreds of these at hubblesite .org/gallery. But here's the truth: if you were looking out of a starship's window in the midst of the Eta Carinae Nebula, it would look not like its dazzling Hubble panorama but about as it looks in a richest-field telescope under a rural sky.

The Pinwheel Galaxy, if seen edge-on up close through your starship's window, would look about like the Milky Way does on a dark night in the country.

Spectacular photos show what you would see if your eyes had different specifications: if, perhaps, they were as large as gymnasiums with pupils 8 or 10 meters across, perfect focus, and--most importantly of all--a super retina with fantastically sensitive pixels able to see in all sorts of adjustable wavebands, many of them outside the human range.

A bigger divergence from reality comes in space artwork. The best space artists try to show what you would see if you were there, but even if they've studied up thoroughly and know what to show (many don't), paint on canvas or pixels onscreen are pathetically weak media. And artists routinely add physically impossible flourishes for effect.

Yet images are powerful. Too powerful. Your unconscious mind takes them at face value as real, even if your conscious mind knows the ways they're not. So people end up confused about all kinds of things in astronomy.

So get up from the screen, go out, and observe with your eyes. They show the slice of reality you are born to interpret best. What you experience directly--dim and distant as it may be--really is the closest you can come to the real thing.

Alan M. MacRobert is editor of SkyWatch.

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Title Annotation:Final Observations: Alan MacRobert
Author:Macrobert, Alan
Publication:SkyWatch
Date:Jan 1, 2015
Words:566
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