The wide-field view of the Cygnus Loop was taken with the WIYN 0.9-meter at KPNO. Credit score: T.A. Rector (College of Alaska Anchorage) and WIYN/NOIRLab/NSF/AURA.
The Cygnus Loop is without doubt one of the most spectacular examples of a veiled stellar corpse that’s accessible to small telescopes. Its seen streamers type the filamentary stays of an unknown supergiant star that erupted as a supernova some 5,000 to eight,000 years in the past.
Most observers take pleasure in searching for out the Loop’s brightest segments, NGC 6992 and 6960. However do you know that the Loop’s lesser ghostly wisps are also inside attain of small telescopes? Probably the most conspicuous of them carries no correct classification. Often known as Fleming’s Triangular Wisp, this phantom characteristic is without doubt one of the longest and most lacelike constructions within the complicated, and it could have contributed to the Loop’s standard moniker: the Veil Nebula.
Williamina Paton Stevens Fleming (1857–1911) found this 3°-long rivulet of nebulous streamers whereas inspecting photographic plates. Fleming was one of the crucial celebrated girl astronomers at Harvard Faculty Observatory (HCO). Except for recording stars for the Henry Draper Catalogue, her work led to the invention of 10 novae, 52 nebulae (together with the Horsehead Nebula in Orion, the White-Eyed Pea Nebula [IC 4593] in Hercules, and planetary nebula IC 2149 in Auriga), and 310 variable stars.
Fleming found the Triangular Wisp on Jan. 13, 1905, whereas inspecting a 240-minute publicity taken Sept. 2, 1904, at Harvard’s outpost in Arequipa, Peru, with the 24-inch Bruce Telescope. (The telescope was named after Catherine Bruce, who gifted the cash for its buy.) On the glass plate’s sleeve, Fleming refers back to the discover within the third particular person, writing: “Nebulosity marked by W. P. Fleming. Virtually Full Circle.”
HCO Director Edward C. Pickering introduced Fleming’s discovery in Harvard Round quantity 111, dated Feb. 16, 1906: “From an examination of this plate, Mrs. Fleming discovered that the northern and maybe southern ends of [NGC 6960 and 6992] are linked by faint nebulosity forming an irregular oval. A big triangular wisp of nebulosity extends southward, from the north previous portion of this oval, and is far more conspicuous than the neighboring nebulae, NGC 6974 and NGC 6979.”
Pickering’s notice clarifies that Fleming’s Triangular Wisp isn’t NGC 6979, as it’s typically attributed right now. Each Fleming’s authentic notice and Pickering’s announcement additionally make clear that Fleming was the primary particular person to detect the Cygnus Loop.
By way of a small telescope, Fleming’s Triangular Wisp is a haunting spectacle. Its ghostlike visage floats between the braided fishhook of nebulous streamers to the east (NGC 6992/5 and IC 1340) and the bristling sweep of nebulosity often called the Witch’s Broom to the west (NGC 6960).
The visible problem is to make use of average powers to detect filamentary construction within the triangular head. Are you able to hint the veil to its southern excessive, the place it seems to curve westward? From a darkish web site, your entire inside arc is outstanding sufficient to idiot an unwary observer into believing that they’ve seen the Veil’s easternmost phase. The perceived dimensions of those fainter options are tentative as a result of they have an inclination to observe star streams, and it’s laborious to evaluate the place the nebulosity ends and the star streams start.
A veil looks like a becoming label for these nebulous streamers, and never only for its look: Bridal veils date to Roman occasions, after they have been used not solely in marriage however in dying as a burial shroud — applicable for the stays of a stellar corpse.
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