The Veil Nebula, the tattered remains of an ancient supernova explosion, is one of the most spectacular objects in the night sky. Did you know it has two dozen parts visible in amateur telescopes?
Ever wish you could go back in time? I mean way back. Amateur astronomers are no strangers to time travel. We all know that the mere act of looking up means watching the clock spin backwards. So imagine hopping off your time machine around the year 6000 BC, several thousand years before the first pyramid arose in Egypt.
On that distant date, assuming favorable viewing circumstances, your gaze would have been transfixed by a star brighter than Venus below the left mid-wing of Cygnus the Swan. Here, a supergiant star 20 times more massive than the Sun called it a day, collapsing and rebounding in a spectacular supernova explosion. A glowing remnant, the Veil Nebula, has been expanding in the death-star's wake ever since. Eight thousand years later, even a small telescope reveals this wreath of thermonuclear wrath.
Giant stars are notorious for losing mass in the form of high-speed winds of subatomic particles and dust. Astronomers suspect that strong winds from the progenitor star blew a large, roughly spherical cavity into the surrounding interstellar gas long before the explosion. Later, when the star self-destructed, the expanding shock wave slammed into the shell, heating and exciting the gas to glow.
Since the cavity walls aren't perfectly uniform — gas density varies from location to location — the brightness of the Veil Nebula varies. Where the density is thick, the shock wave creates a bright filament in the cavity wall; where it's thin or nonexistent, we see more diffuse emission or missing sections. It's amazing to realize that the shock wave is still plowing through the interstellar gas at nearly a million miles an hour (40 km/second) in places.
This video shows the movement of the gas filaments within the Veil Nebula from 1997 to 2015 using the Hubble Space Telescope.
NASA / ESA / Hubble Heritage Team
To this day, the Veil continues to balloon outward. Photos taken with the Hubble Space Telescope in 1997 compared with those from 2015 clearly show individual filaments on the move. The strands comprising the eastern and western arcs of the Veil appear especially bright because we're viewing them tangentially, or edge-on — the same as looking at a wrinkled bed sheet from the side.
The Veil Nebula is surprisingly easy to see in a smaller scope, especially if you use a UHC or OIII nebular filter. I was shocked when I attempted it in 10x50 wide-field binoculars recently. Under a Bortle class 3 sky without a filter I easily spotted the southern spread of the western Veil as a faint haze extending south of the star 52 Cyg, while the eastern, crescent-shaped portion was immediately visible as a nebulous arc with variations in brightness along its curve. Yes, in binoculars.
The brighter sections of the nebula bear unique catalog numbers and/or nicknames:
- Western Veil, or NGC 6960 ("Finger of God" or "Witch's Broom"). This section is centered on the bright star 52 Cyg. The northern half looks like a sharp fang with a darker center. The southern half divides into parallel ribbons reminiscent of the summertime Milky Way.
- Eastern Veil, or NGC 6992, is the brightest part and composed of multiple, interwoven strands of nebulosity. NGC 6995 is a bright arc of material at the south end of 6992 that unfurls to the west; together they're known as the "Network Nebula." IC 1340 is a bright condensation in the arc parallel to and immediately south of NGC 6995.
- NGC 6979 and NGC 6974 are two fainter hunks of diffuse nebula between the two main arcs and a short distance east of the magnificent Pickering's Triangle, a prominent bright section shaped like a goatee and trailing a long, winding strand of nebulosity. The Triangle is also cataloged as Simeis 3-188.
- Simeis 3-210 is a brighter patch of nebulosity at the remnant's southern border.
But these regions only scratch at the surface of what you can see.There are at least a dozen more nebulous knots, patches and strands strewn about the ~3°-wide field of view encompassed by the remnant. You can easily spend your entire observing session right here. I sure did!
Through an old University Optics 80mm f/6.25 refractor with a UHC filter and 25x eyepiece, I could make out both halves of the Veil and even part of Pickering's Triangle. These smaller instruments whetted my appetite for a look through my 15-inch Obsession with the OIII narrow-band filter and a low magnification (64x), wide-field eyepiece.
Even under inky, rural skies, a nebular filter is a powerful tool because of its ability to block natural skyglow. Screw one into your eyepiece and watch the nebula come alive with curving and twisty strands that appear to hover in 3D against the starry backdrop. The Veil rightly elicits nearly as many wows as Saturn or your favorite globular cluster.
Parting the Veil
I like to start west and move east, so we begin with NGC 6960, a bright section of nebula "split" into two very different halves by the glare of 52 Cygni. To the north I see a hollow fang outlined by sharp, bright filaments. Higher magnification makes its darker center more obvious. If you switch back and forth from direct to averted vision, the fang appears to sharpen and pulse as if in attack mode. Scary stuff, the heavens.
The southern half unfurls in graceful ribbons of nebulosity. Two streamers are bright and obvious, a third one to the east fainter and more diffuse. In the old days, I'd call it good at this point and move 2.3° to the northeast to study the other half of the nebula. Instead, I take my time, put on some boots and follow the ribbons' arc southward into a lagoon of faint, patchy nebulosity. The brightest, most obvious piece is labeled D in the map and looks a bit like the letter F. You can't miss it. The regions labeled C, B, I and J are fainter, diffuse condensations wedged between the Western Veil and the southern reaches of what I call "The Funnel." More on that in a minute.
Gummy Worms and a Goatee
Continuing southeast we come to Simeis 3-210 (labeled A), an obvious fuzzy glow that extends southwest of a 6th magnitude star at the apex of a nearly equilateral triangle with two other 8th magnitude stars. All are circled on the map. Although I left it unlabeled, there's an additional small patch immediately northeast of A, a "Mini-Me" nebular companion. Once you've found these, use averted vision to spy the larger, diffuse K-cloud.
Like eating an ear of corn, let's head back north again and chew our way south beginning with the amazing Pickering's Triangle, a tangle of wormy filaments and vacant holes that narrows into a bright goatee of sorts before morphing into what looks like a squiggly gummy worm or the neck of a funnel. This is one of my favorite sections of the Veil — take a look and share your impression with us. Oh, and don't miss out on E, a prominent, arc-shaped patch just west of the Triangle and one of the easiest pieces.
I know you're eager to get to the Eastern Veil, but we have a few more stops, notably the trio of wisps L, G and M. L is the brightest and most condensed of the three; G a little fainter and more diffuse and M the faintest and largest. With averted vision, it looks like an old man's bushy eyebrow. NGC 6974 and NGC 6979 are side-by-side, mottled blobs of glowing gas; to their west look for a short, chalky streak labeled F.
The Eastern Veil is just over a degree long, so I can barely squeeze it all into one field of view. Each section or NGC / IC number possesses its own unique character: the northern third bright and thick with lacework reminiscent of beaming auroral columns; the mid-section fainter and sliced into multiple, parallel streaks, and the south third nothing short of a revelation. Is there anything in the heavens that looks as terrifyingly beautiful as these crusty, ribbed arcs, so bonelike in appearance you can practically hear them rattle on frosty nights?
At the far terminus of IC 1340, a small, bright feather of nebulosity (N) points the way south back into the open sea of stars. Our journey ends at the bright, nebular shoal H, where we might look back across the 110-light-year span of the Veil to appreciate how far we've come.
Resources / Notes:
* For consistency, I labeled the smaller parts of the Veil Nebula after Alan Whitman's lettering system as described on Steve Gottlieb's Veil Nebula page but extended it to 14 distinct features.
* Cygnus Loop and Veil Nebula — More about the Veil's amazing structures and how they came to be.