Learning to see

As with any wor­thy endeavor, it takes time to become a good stargazer. Even the small­est tele­scopes and binoc­u­lars are space­ships to other worlds, but you have to learn to run the controls.

Most of all, you have to train your eyes and heart to see. Your ini­tial views of star clus­ters and galax­ies are inevitably dis­ap­point­ing. They look at first like balls of lint. Where are all the details vis­i­ble in those long-exposure pho­tographs you see on the Internet?

The details are there, oh ye frus­trated stargaz­ers. The longer you look, the more you will see.

A deep-sky object is any­thing out­side our solar sys­tem. The cat­a­logs of these astro­nom­i­cal splen­dors tend to include every­thing that isn’t a star and appears at first as a fuzzy patch in astro­nom­i­cal instru­ments of small size.

The mother of all deep-sky objects is the Great Neb­ula in the sword of Orion. In a small tele­scope, you will see a tiny patch of glow­ing gas sur­round­ing a rough square of four stars called the Trapezium.

Don’t look away. Try to catch the light patch out of the cor­ner of your eye, a tech­nique called averted vision. Look at the edge of the field of view and not at its cen­ter. The Great Neb­ula will explode into com­plex swirls, a cloud of gas where stars are being born at the very moment you are read­ing these lines.

Averted vision is also help­ful at the end of stel­lar evo­lu­tion. As stars die, they shed their skins and form a sphere of glow­ing gas. The dead star glows less brightly at its cen­ter, usu­ally as a col­lapsed white-dwarf star.

The clas­sic case where averted vision will help you is the Blink­ing Plan­e­tary in the con­stel­la­tion Cygnus. (Sorry. You’ll have to wait for sum­mer to see it.) Stare directly at it in a tele­scope and you will see only the cen­tral star. Use averted vision and a tiny blue snow­ball will appear around the star. Glance away and toward the object, and the blue ball will appear and dis­ap­pear as if by magic.

Another clas­sic case is the star clus­ter des­ig­nated as M35 in the Messier Cat­a­log of deep-sky objects. M35 is easy to find and makes a great intro­duc­tion to this “harder” class of tele­scopic objects.

Just after dark, look for the con­stel­la­tion Gem­ini high in the east. You’ll see two bright stars, called Cas­tor and Pol­lux, of equal bright­ness hud­dled fairly close together. Two par­al­lel strings of bright stars extend to the south from Cas­tor and Pol­lux. Fol­low the upper string and hang a left.

In binoc­u­lars, you will see a small­ish, round blob of light. You’ve found M35.

Look just to the side of it, and view the light with your periph­eral vision. After a time, the light will look lumpy, with patches a lit­tle brighter than the rest. The blob is now a struc­tured blob.

Now turn to your tele­scope. Even in a small instru­ment, the blob will resolve into a few bright stars caught in an unre­solved haze.

You see so lit­tle because your brain is drawn to what is most eas­ily seen. You must trick your eye to see more.

Use your periph­eral vision again. Slowly, you will see more and more stars as your eye trains itself to see what’s really there. Even­tu­ally, you will see at many as 50 stars sur­rounded by the haze of hun­dreds of unre­solved stars that fill the spaces among the brighter points.

But don’t stop there. You have learned to see, but the process has just begun.

Now con­sider what you are see­ing. M35 is sev­eral hun­dred stars crowded in a region about 30 light years (180 tril­lion miles) wide. It is per­haps 2,800 light years distant.

A few of the stars are yel­low or orange. They are giant stars that have reached matu­rity and beyond. Hav­ing lived a quick and vio­lent life, they will soon perish.

Most of the stars are hot and blue, mean­ing they are newly formed from the enor­mous hydro­gen cloud that gave them birth. The clus­ter was born only 50 mil­lion years ago, a snap of the fin­gers com­pared to our 5-billion-year-old sun.

Learn­ing to see is more than a trick of the eye. When you know at last what you are see­ing, when you learn the mean­ing of the stars, only then will you be trans­ported to dis­tant worlds.

Tom Burns is the direc­tor of Perkins Obser­va­tory. He can be reached at tlburns@owu.edu.

Posted by Tom Burns on Jan 13 2013. You can follow any responses to this entry through the RSS Feed. Comments can be made below.