About the name Cocoon Nebula

[wvreeven]

Hi all,

I am trying to trace the origin of the name Cocoon Nebula for IC 5146. Does any of you know?


Clear skies,

Wouter

[Mark McCarthy]

A bit of Google searching turned up this: "Discovered by Thomas Espin, it has often been referred to as the “Cocoon” because it lay at the end of a long and fairly starless trail – like the proverbial worm who ate its way to the end of the leaf before time for change."

http://www.universetoday.com/15412/the-cosmic-cocoon-ic-5146-by-tom-v-davis/

[wvreeven]

Thanks Mark! Apparently my Googling isn't as efficient as yours...

[Preston Pendergraft]

Sometimes names don't always make sense because we as visual observers don't see all the detail that the photos show. A good example is the Crab Nebula or the Eagle Nebula.

[Steve Gottlieb]

A bit of Google searching turned up this: "Discovered by Thomas Espin, it has often been referred to as the “Cocoon” because it lay at the end of a long and fairly starless trail – like the proverbial worm who ate its way to the end of the leaf before time for change."

http://www.universetoday.com/15412/the-cosmic-cocoon-ic-5146-by-tom-v-davis/

A bit more on the discovery -- The Reverend Thomas Espin found the Cocoon Nebula (IC 5146) visually on 13 Aug 1899 and confirmed it on the 15th. He was using a 17.5-inch reflector at Tow Law, England at his private observatory. His description reads "Large, faint glow about 8', well seen each night." No mention of a nickname.

But Wolfgang Steinicke notes that the original discovery was made by E.E. Barnard "on Oct. 11, 1893 with the 6" Willard lens at Lick and independently by Max Wolf with his 6" camera at Königstuhl (July 28, 1894)." I checked Barnard's notes in his photographic atlas for B168, the dark lane leading to the bright nebula, but he doesn't call it the "Cocoon" either (at least in his photographic atlas).

Vehrenberg apparently called it the Cocoon Nebula in his "Atlas of Deep-Sky Splendors", so the nickname has been around for over 30 years.

[Love Cowboy]

Sometimes names don't always make sense because we as visual observers don't see all the detail that the photos show. A good example is the Crab Nebula or the Eagle Nebula.

Actually the Crab Nebula is a bad example of your point. That name was derived from a really bizarre sketch of the object from Lord Rosse's visual observation of it in his 36". Despite Lord Rosse's repudiation of said sketch after re-examining the object in his 72" "Leviathan of Parsonstown", the name had already stuck somehow.

[Steve Gottlieb]

Here's (http://messier.seds.org/more/m001_rosse.html) William Parsons' sketch in 1844 of the Crab Nebula with his 36-inch. Later Dreyer (who was an assistant on the 72-inch) wrote "The only published drawing which is a complete failure, is that of M1, the "Crab Nebula", which has unfortunately been reproduced in many popular books. It was made with the 3-foot, and long "feelers" were never again seen with the 3-foot nor with the 6-foot."

[Steve Gottlieb]

I know some of you are aware the discussion about the Cocoon Nebula nickname ended up on another forum (AMASTRO) and I was able to track down the source. If you missed that discussion, it turns out the nickname is 110 years old. Here's the background ...

Max Wolf photographed the field on 28 Jul 1894 with the 6-inch camera at Königstuhl. He announced the discovery in MNRAS, 64, 838 (1904) and included an excellent photograph taken on 10 Jul 1904, along with a discussion of the dark lane and nebula. The article is titled "Remarkable nebula in Cygnus" though he doesn't mention the nickname "Cocoon Nebula" in his discovery paper.

But Agnes Mary Clerke, who was in correspondence with Wolf at the time, includes his 1904 photograph (plate XX) in her second edition (1905) of "The System of the Stars". She labeled the photograph "The Cocoon Nebula in Cygnus" and writes (p. 352) "The depicted nebula, which had been discovered ten years previously, is about 10' in diameter, of a round shape, and a complex structure. "It is placed centrally," Dr. Wolf writes, "in a very fine lacuna void of faint stars, which surrounds the luminous cloud like a trench." Moreover, this negative "halo forms the end of a long channel, running eastward from the western nebulous clouds and their lucanae, to a length of more the two degrees." The coexistence in the same sidereal district of nebulae and stars could not well be asserted with stronger emphasis than by clearly of a dark fosse for the accommodation of the cocoon-like object [emphasis added] in Plate XX."

[wvreeven]

And, like I did on amastro, let me add my gratitute to all trying to unravel this mystery!