Starship Asterisk*

APOD Robot wrote:
Colored pencils on white paper were used to create the original drawing, shown here digitally scanned with an inverted palette applied.

http://en.wikipedia.org/wiki/Der_Ring_des_Nibelungen wrote:

<<Der Ring des Nibelungen is a cycle of four epic operas by the German composer Richard Wagner (1813–83). The works are based loosely on characters from the Norse sagas and the Nibelungenlied. The operas, which the composer described as a trilogy with a Vorabend ("preliminary evening"), are often referred to as the Ring Cycle, Wagner's Ring, or simply the Ring. Wagner wrote the libretto and music over the course of about twenty-six years, from 1848 to 1874. The four operas that constitute the Ring cycle are, in sequence:

• Das Rheingold (The Rhine Gold)
  Die Walküre (The Valkyrie)
  Siegfried
  Götterdämmerung (Twilight of the Gods)

Wagner's title is most literally rendered in English as The Ring of the Nibelung. The Nibelung of the title is the dwarf Alberich, and the ring in question is the one he fashions from the Rhinegold. The title therefore denotes "Alberich's Ring". In German the "-en" ending of "Nibelungen" and the article "des" preceding it denote the possessive (genitive) singular case. "Nibelungen" is occasionally mistaken as a plural.>>

NoelC wrote:
He has a 40 inch telescope with optics good enough to see the central star of the Ring, under skies dark enough and with enough light gathering ability to sense color in the Ring, and finally, the ability to be comfortable for long enough at the eyepiece to draw a significantly good picture... Mmmmm! Observational astronomer nirvana has been achieved.

• In a 40" telescope: just a 5th magnitude star!

http://en.wikipedia.org/wiki/Ring_Nebula wrote:

[b][color=#0000FF]Reconstructed tower of Hahn's private Remplin Observatory Friedrich II. Graf von Hahn (July 27, 1742 – October 9, 1805) was a German nobleman, a philosopher and astronomer. In 1800, he discovered the central star in M57, the Ring Nebula.[/color][/b]

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<<The famous Ring Nebula (also catalogued as Messier 57, M57 or NGC 6720) appears in the northern constellation of Lyra. It is a prominent example of a planetary nebula. This is a shell of ionized gas expelled into the surrounding interstellar medium by a red giant star, which was passing through the last stage in its evolution before becoming a white dwarf.

The nebula disk has an angular size of 1.5 × 1 arcminutes, making it too small to be resolved with 10×50 binoculars. It is best observed using a telescope with an aperture of at least 8 in, but even a 3 in telescope will reveal its elliptical ring shape. The interior hole can be resolved by a 4 in instrument at a magnification of 100×. Larger instruments will show a few darker zones on the eastern and western edges of the ring, and some faint nebulosity inside the disk. The central star, at magnitude 14.8, is difficult to spot.

M57 has a visual magnitude of 8.8v and photographic magnitude of 9.7p. Photographs taken over a period of 50 years show the rate of nebula expansion is roughly 1 arcsecond per century, which corresponds to spectroscopic observations as 20–30 km s−1. M57 is illuminated by a central white dwarf or planetary nebula nucleus (PNN) of 15.75v visual magnitude, whose mass is ~1.2 M_☉.

All the interior parts of this nebula have a blue-green tinge that is caused by the doubly ionized oxygen emission lines at 495.7 and 500.7 nm. These observed so-called "forbidden lines" occur only in conditions of very low density containing a few atoms per cubic centimeter. In the outer region of the ring, part of the reddish hue is caused by hydrogen emission at 656.3 nm, forming part of the Balmer series of lines. Forbidden lines of ionized nitrogen or [N II] contributes to the reddishness at 654.8 and 658.3 nm.

This nebula was discovered by the French astronomer Antoine Darquier de Pellepoix in January 1779, who reported that it was "...as large as Jupiter [~ 50"] and resembles a planet which is fading." Later the same month, fellow French astronomer Charles Messier independently found the same nebula while searching for comets. It was then entered into his catalogue as the 57th object. Messier and German-born astronomer William Herschel speculated that the nebula was formed by multiple faint stars that were unresolvable with his telescope. In 1800, German Count Friedrich von Hahn announced that he had discovered the faint central star at the heart of the nebula a few years earlier. He also noted that the interior of the ring had undergone changes, and said he could no longer find the central star. In 1864, English amateur astronomer William Huggins examined the spectra of multiple nebulae, discovering that some of these objects, including M57, displayed the spectra of bright emission lines characteristic of fluorescing glowing gases. Huggins concluded that most planetary nebulae were not composed of unresolved stars, as had been previously suspected, but were nebulosities. The nebula was first photographed by the Hungarian astronomer Eugene von Gothard in 1886.>>

Psnarf wrote:
It was only recently that astronomers determined that we are looking down the barrel of a cylinder from one of the poles, not a ring. http://messier.seds.org/m/m057.html

I have to wonder about the magnitude of the probability that the pole just happens to be pointed in our direction so that we can see down the barrel (or torus). Is this serendipitous orientation similar for all ring nebulae? The age determined by winding back the clock of the known expansion rate suggests that folks living between 6,000BCE - 4,000BCE could have witnessed the explosion. Might there be glyphs, pictographs or neolithic symbols that chronicle the event?

Psnarf wrote:I have to wonder about the magnitude of the probability that the pole just happens to be pointed in our direction so that we can see down the barrel (or torus). Is this serendipitous orientation similar for all ring nebulae?

KarelVreeburg wrote:
I wonder why you name objects like this Ring Nebula's , because they are not, is is a Hour Glass Nebula
seen from the top, ( or the bottom). It has a huge 3-D shape nothing like a ring. Karel Sculptor

The sketch was made with 800x magnification and excellent seeing conditions directly at the eyepiece of a 40 inch reflecting telescope.

Czerno 1 wrote:

The sketch was made with 800x magnification and excellent seeing conditions directly at the eyepiece of a 40 inch reflecting telescope.

What would be the physical size of the actual image at the eypiece (and original drawing) ?