Editor's note: Portions of this have been previously published on the author's blog.
A dazzling gem of the nighttime summer sky is the Lagoon Nebula, a gigantic star-nest relatively near our planet (as cosmic distances go). It's bright enough that from a dark site, a person supposedly can see it with unaided eyes, toward the lower part of the southern Milky Way.
During a visit to a site that Utah astronomers call Pit ‘n Pole, in Tooele County, I was awed by the beauty of the night sky: Jupiter blazed as it sank in the west and the Milky Way stood up from the south like a streak of gray smoke. (I didn’t notice it but Saturn was in the middle of that section, too.) The Teapot, a formation of eight stars in the Sagittarius constellation, was tilted so that the filmy center of our galaxy, the Milky Way, puffed around its spout.
After midnight a couple of coyotes yapped at each other, too far away to record by iPhone.
I was there to try out my new astro-camera, which had been difficult to learn. My first attempt that night was a portrait of NGC 6946, the galaxy where Patrick Wiggins discovered his most recent supernova. I had been anxious to get a view of it ever since Wiggins noticed it on May 13. In fact, I'd planned to set up my telescope in the backyard that same night and photograph the same galaxy, as it’s one of my favorites. But we had guests, so I didn’t try, and it turned out later that NGC6946 would have been blocked by trees — and I had equipment troubles that would have prevented any picture.
This time, the host galaxy was in the northeast nearing 60 degrees up toward the apex, where one might think it had cleared all light pollution. But that was exactly the wrong direction from Pit ‘n Pole and still not high enough. NGC6946 floated in the nasty, abundant, high-reaching, murky and abhorrent light pollution from Tooele and Salt Lake City. I took a photo — the supernova remains about as bright as when Wiggins found it — but it’s an unimpressive picture.
Disappointed, I turned the telescope to M8, the emission nebula also known as the Lagoon. Free of extraneous light, the nebula was stunning. Image after image poured onto the laptop screen, showing it in high detail. After some hours I was freezing, but so elated that I didn't care about the temperature drop.
The Lagoon Nebula is a glowing cocoon of gas and dust studded with young stars, only 5,000 light-years away, measuring 100 light-years across. At that distance, according to NASA, it seems to be larger than the diameter of the full moon. It’s a chaos of velvet curtains and folds and streamers of gas, with dozens of stars shining through. Gravity causes surrounding material to condense tighter and tighter until it ignites in nuclear fusion, and a star is born.
The lagoon itself is a curving dark stretch, like a canal, between two lighter pods. (Having grown up on the edge of the world’s biggest lagoon on the Kwajalein Atoll in the Marshall Islands, this object looks nothing like one.)
"The central hot star, O Herschel 36 … is the primary source of the ionising radiation for the brightest region in the nebula, called the 'Hourglass,'" says the European Space Agency. "Other hot stars, also present in the nebula, are ionising (forgive the British misspelling) the outer visible parts of the nebulous material.
"This ionising radiation heats up and 'evaporates' the surfaces of the clouds … and drives violent stellar winds which tear into the cool clouds."
Sometimes the Hourglass is burned out into a larger glare in photographs that are light enough to prevent dimmer regions from fading into the dark background. But with adjustments in brightness and contrast while processing, the hourglass shape comes through.