The Wandering Astronomer

or

Misadventures in Dark Adaptation           

Ahoy, ye scurvy dogs! Batten down the hatches! Swab the gangplank! Hoist up the Jolly Roger, ye swashbuckling knaves, as we plough these white-capped seas in search of ill-gotten gold, bountiful booty, and purses aplenty in unprotected ports. Arr!  May every skirmish with the King’s regiments be another victory for the Devil himself, dancing in the fire-lit caverns where our shades will soon gather to…

Yes, you’re right. Unless they’re standing close to the fried dough stand or ferris wheel, no pirate will ever actually spout such nonsense. Moreover, according to historians who have studied maritime history, being visited by real pirates would ruin what would probably be the last day of your life anyway. Also, a pirate captain would have had to have been unfathomably stupid to have a Jolly Roger pirate flag flapping from the mast. Doing so would have been tantamount to spray painting, “Hey, British Navy, cannonball us first!” on the bow.  All this tedious history notwithstanding, Jolly Roger flags are now inextricably linked with pirate lore and pirate-based theme-park rides. Now, apart from the fact that I just bought a Jolly Roger flag yesterday in order to terrify the staff into unquestioning obedience,  what connection could such a flag possibly have with astronomy?

Look at the eye patch!
Have you ever wondered why pirates wore eye patches? Theories abound, of course, as theories are wont to do.  Many believe that the eye patches were necessary because pirates would often lose an eye in fencing duels or zombie sieges. In fact, the reason might have been less about empty sockets than contracting pupils: dark adaptation.

Let’s say that a pirate is on a ship doing what pirates generally do (and the less said about that, the better.) As a pirate is moving from the lower region to the deck, he (sometimes, she, Grannia), will be exposed to different light levels:   dark and gloomy in the lowest level, fiercely bright on the deck, with various levels of gloaming haze in between. Now, as anybody who has spent 340 years working in a subterranean planetarium without the faintest hope of liberation and far removed from the sympathies of humankind can attest,  ascending out of deep darkness into open sunlight can inflict some pain on ye here soul windows. The pirates would have experienced the same discomfort and, most importantly, might have been temporarily blinded by the sunlight when ascending onto the upper deck. Conversely, they would also have been blinded by the shade when venturing down below. Having a patch on one eye would keep that eye steeped in darkness and therefore always dark adapted. As the pirate rushes down into the ship’s lower regions, he/she could switch the patch from the dark adapted eye to the one that isn’t, thereby preventing the temporary loss of vision.

Our pupils expand and contract in response to light levels. In bright light, the pupils contract for self protection to prevent an excess of incoming radiation. In dim light, the pupils expand to allow for the reception of more light to see. When one wants to have a good view in a dim region, the larger the pupil the better.  (We remember that telescopes are essentially allowing for the gathering of more light so one can gain a much clearer view of a dim celestial object.)

Tonight, if you’re planning to venture outside to admire the sky, you could keep a patch on your eye for about 20 – 30 minutes beforehand. That patch would protect your eye from the micro sources of light pollution: televisions, lamps,  computer screens, smart phones, and the various other trappings of our modern world. You might look like a pirate, but you’ll be able to see the sky like an astronomer. A perfect time to make a comment about moral equivalency, but I won’t.

Quote of the day:

“Philosophers, for the most part, are constitutionally timid, and dislike the unexpected. Few of them would be genuinely happy as pirates or burglars. Accordingly they invent systems which make the future calculable, at least in its main outlines.” -Bertrand Russell