April 13, 2015

Drawing the Great Nebula

This past Saturday, I indulged in some quiet time alone under a dark sky, and spent a couple hours sketching the Orion Nebula before it disappeared behind a lacy horizon of budding spring trees. I've had a soft spot for star-forming nebulae--especially M42 in Orion's Sword and The Lagoon in Sagittarius--ever since I started observing. Even though they're not hard to find, and flamboyant photographs of them are so ubiquitous they've almost become a cliche, I've never tired of spending long minutes at the eyepiece soaking in the depths of their faintly glowing obscurity.

At a BRAS public observing session a couple weeks ago, I trained my year-old 12 inch Dob on the Orion Nebula and was stunned to see it glowing a pale green. Detecting color during low-light observing is not the norm. Except for the planets and some stars, deep-sky viewing is typically a low-contrast black-and-white affair. This has never been a problem for me. In fact, I've always preferred the aesthetics of what my eye sees over the oversaturated astronomical photographs that have become the norm. Still, catching that new hint of color with my own eyes...a translucent sea green edged by the barest whisper of maroon (the glow of ionized oxygen and hydrogen)...it seemed almost magical.

I wanted to look all night.

But, it was public observing. People want to see other stuff. And everyone else around me was bouncing around to different objects as well. My desire to keep up with the hunt overrode everything else. So, I resolved to find some other night when I could go out on my own, undistracted, take a sketchpad, and shamelessly delve into Orion's jeweled sword for as long as the horizon would allow.

I borrowed my first telescope in 2007. It was an 8 inch Dobsonian loaned to me by the Salt Lake Astronomical Society. One morning before work, I woke up in the dark hours before sunrise, set the telescope on the back porch of my condo in Holladay, trained it on Orion's sword, gathered some drawing materials in a lit hallway around the corner, and started sketching. I'd look through the eyepiece for several seconds, memorize the view, and then dash into the hallway to record what I'd seen. Here's the result (with diffraction spikes added to the brighter stars...just because).

I didn't see any color that morning...not a big surprise...8 inches probably doesn't collect quite enough light for that, and my neighbor's porch light was shining in my eyes the whole time...and yes, I was going back and forth between my porch and my own lighted hallway. In other words, conditions were not ideal. Still, I found the view utterly enchanting. And though I lost the original sketch in during one of my many recent moves, it remains one of my favorites.

This Saturday's observing was a whole different animal. Now equipped with 4 more inches of telescopic aperture, I was parked outside in a relatively dark place (for norther Ohio), and kept the white lights off so as to allow my eyes to fully dark adapt. I had a small red flashlight, but trying to sketch white-on-black under a dim red glow was quite a challenge. I soon found that attempting any kind of color would be impossible. My best bet would be to sketch for contrast, and then add finer nuances of color by memory at home later. I sat with my sketchpad on my knee, and a bag of colored pencils in my pocket, studying what faint details I could make out through a low-magnification wide-field eyepiece, while slowly nudging my telescope forward with the earth's rotation. A shrill chorus of spring peepers bloomed in the distance, occasionally punctuated by the strange hoots and calls and trills of night creatures in the surrounding woods.

After finishing this sketch, I got curious about how others have interpreted Orion in the past.

Charles Messier, the infamous non-comet-hunter himself, published this drawing in 1771:

And here's what Sir John Herschel saw in the 1830s--note the trapezium at center:

Lord Rosse had an interesting eye for it in the 1850s:

And recording Orion in unprecedented detail was the final work of George Phillips Bond, the second director of the Harvard Observatory. While enduring a terminal case of tuberculosis, he sat in the frigid observatory night after night desperately trying to complete a series of sketches and surveys. He died in 1865 at the age of 39, his work on Orion still in progress.

Etienne Leopold Trouvelot--one of my favorite astronomical artists--made these charcoal sketches a few years later...

...so interesting to note the subtle differences in each one. Imagine using a series of images like this for real scientific inquiry. This was the height of technology at the time...but not for long.

In 1883, Henry Draper made this first photograph of the Trapezium and vicinity:

...followed soon after by this long-exposure image by Andrew Ainslie.

With the advent of photography it was now possible to see details far beyond those allowed by the human eye.

And the rest, as they say...

Truth-be-told, I still much prefer what my eye can see. And sometimes I like to imagine there are others who feel the same way. Doing a search for "Orion Nebula" on the Astronomy Sketch of the Day website yeilds a treasure trove of modern interpretations of this ancient wonder. Maybe you'd even care to add your own.