Sagittarius, the Archer

My first expe­ri­ence with ama­teur astron­omy was not a good one. I couldn’t find any­thing in my crude, home-built telescope.

I had heard that mem­bers of the astron­omy club did their stargaz­ing at a site north of Colum­bus. I decided one clear night to go there and ask for some help.

When I got there, I had to carry my scope down a long, dark, wooded path. Ahead was an open­ing in the trees, and the mem­ory of what I saw in it still brings a lump to my throat after all these years. The open­ing was full of stars.

As I got closer, I saw the dark sil­hou­ette of a dozen or so peo­ple hud­dled over their tele­scopes against the back­drop of the bril­liant glow of the Milky Way in the con­stel­la­tion Sagit­tar­ius, the Archer.

Sagit­tar­ius looks more like a teapot than an archer, and that’s how most stargaz­ers rec­og­nize it these days. But even that image doesn’t work for most mem­bers of the lat­est gen­er­a­tions. Tea comes in bags now. Not too many peo­ple use teapots anymore.

New­com­ers tend to attract a lot of atten­tion at these infor­mal “star par­ties.” Where had I got­ten my scope? Had I built it myself? Would I like to see some­thing in it?

Would I!

They gave me the grand tour of the sky, with empha­sis on Sagit­tar­ius, which is laden with so-called “deep-sky objects.” They are astro­nom­i­cal objects like star clus­ters and gaseous neb­u­lae that are out beyond our solar system.

Sagit­tar­ius is in the direc­tion of the cen­ter of the galaxy where the Milky Way is dens­est with stars and the hydro­gen gas they are formed out of.

They started with the glob­u­lar clus­ter M22, just to the left of the top of the “teapot.” In binoc­u­lars it is a small, round fuzzy spot. In my tele­scope, it exploded into a ball of count­less small stars.

Next they showed me M28, which is just above the tip of the lid of the teapot. It is a smaller, fainter ver­sion of M22.

After that we looked at M8, the Lagoon Neb­ula, which is right above the spout of the teapot. In binoc­u­lars it looks like an oval hazy patch. In the tele­scope, it looked like a large milk spill with a long, dark, lagoon-like inden­ta­tion at its center.

The Lagoon is an “emis­sion neb­ula,” a stel­lar nurs­ery where new stars are form­ing out of the raw hydro­gen of the galaxy. Slowly, parts of the hydro­gen gas in the Lagoon are col­laps­ing by grav­ity into balls of hydro­gen. When the pres­sure is great enough, the hydro­gen begins to form helium in a giant ther­monu­clear reac­tion that will last per­haps 10 bil­lion years.

Just above the Lagoon is M20, the Tri­fid Neb­ula. It is another stel­lar nurs­ery. It gets its name from the dark lines that split it into three parts, like a cos­mic peace symbol.

Neb­u­lae are the rea­sons that stars tend to be found in clus­ters. Many stars are cre­ated out of a sin­gle, gigan­tic cloud of hydro­gen. When the stars have formed and the remain­ing gas has dis­si­pated into space, we are left with many stars close together.

Such “galac­tic clus­ters” are found in great abun­dance in Sagit­tar­ius. They showed me M21, dozens of stars that are vis­i­ble in the same tele­scope or binoc­u­lar field as the Tri­fid Neb­ula. They also showed me M25, a clus­ter of about four-dozen stars. It’s up and to the left from the lid of the teapot and is bright enough to be seen in a small ‘scope or binoculars.

Up and to the right from M25 was M24, which was much larger than the other objects. M24 is a “star cloud” of the Milky Way, a dense aggre­ga­tion of stars, star clus­ters and hydro­gen clouds. We swept slowly across its length in my telescope.

Directly above M24 was M18, a small clus­ter of about a dozen stars.

Above M18 was another glow­ing emis­sion neb­ula called M17. It looks like a ghostly check­mark float­ing in space.

The tour of the area ended with a glimpse of another neb­ula, M16, right above M17. M16 is called the Eagle Neb­ula because it has a small dark patch in it that resem­bles a fly­ing eagle.

Dri­ving home, I felt myself a part of a uni­verse so grand and com­plex that my mind was inca­pable of grasp­ing it.

But my heart understood.

In case you haven’t guessed, that place — the place where my love of the starry vault became per­ma­nently fixed — was Perkins Observatory.

If my obses­sion with pro­tect­ing that place from the grow­ing stain of light pol­lu­tion seems unusu­ally obses­sive, please note: Every time we show new­com­ers the stars, we do for them what humans have done since they first looked up at the sky. We pass the knowl­edge of the heav­ens on to the next generation.

In doing for other begin­ners what my men­tors did for me, I pay back a tiny por­tion of the debt I owe them, a debt I can never repay. But, by heaven, I will cer­tainly try.

Tom Burns is the direc­tor of Ohio Wes­leyan University’s Perkins Obser­va­tory. He can be emailed at tlburns@owu.edu.

Posted by Tom Burns on Aug 14 2011. You can follow any responses to this entry through the RSS Feed. Comments can be made below.