Starship Asterisk*

Psnarf wrote:Here in the Sonoran Desert, we have coyotes that start whooping it up at moonrise. I didn't know that the Atacama Desert could support feral donkeys.

neufer wrote:

JonStar wrote:
Our constellations (Orion, Cancer, etc) -- how many are they all located in our Milky Way Galaxy?

In the sense of today's APOD:

Cygnus, Lacerta, Cepheus, Cassiopeia, Perseus, Auriga, Orion/Gemini, Monoceros, Canis Major, Puppus, Vela, Carina, Crux
/ Musca, Centaurus, Circinus, Lupus/Norma, Scorpius, Sagittarius, Ophiuchus, Scutum, Aquila, Sagitta, Vulpecula.

http://media.skysurvey.org/interactive360/index.html

Cpt. Obvious wrote:

neufer wrote:

JonStar wrote:
Our constellations (Orion, Cancer, etc) -- how many are they all located in our Milky Way Galaxy?

In the sense of today's APOD:

Cygnus, Lacerta, Cepheus, Cassiopeia, Perseus, Auriga, Orion/Gemini, Monoceros, Canis Major, Puppus, Vela, Carina, Crux
/ Musca, Centaurus, Circinus, Lupus/Norma, Scorpius, Sagittarius, Ophiuchus, Scutum, Aquila, Sagitta, Vulpecula.

http://media.skysurvey.org/interactive360/index.html

Perhaps worth clarifying, that one cannot observe individual stars outside our galaxy with the naked eye. I presume the second group consists of stars not in the plane of the milky way, but do belong to it (they are 'above' and 'below' us).

http://en.wikipedia.org/wiki/R136 wrote:

R136a was once thought to be a hypergiant star of about 1500 solar masses, 32 million times as bright as the Sun, with a surface temperature of 55–60,000 K and about 50 million miles in diameter.[7] R136a's true nature was resolved by holographic speckle interferometry and found to be a dense star cluster[8] containing, among other things, twelve very massive and luminous stars in its core.[9] These stars had initial masses calculated to be in the range of 37 to 76 solar masses.[9] Three extremely luminous stars (R136a1, R136a2 and R136a3) dominate the cluster and are separated by only 0.10 and 0.48 arcsec. One of the stars, R136a1, is the most massive star found to date with 265 solar masses,[10] as well as the most luminous at 8,700,000 times the brightness of the Sun.[11]

Rhob wrote:
Didn't I read, probably somewhere here on the Asterisk, that every star we can see with the naked eye is within about 55 ly of Sol?

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

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<<Rho Cassiopeiae is a yellow hypergiant star in the constellation Cassiopeia. It is about 8,200 light-years (2,500 pc) away from Earth, yet can still be seen by the naked eye (in the Northern Hemisphere only), as it is 500,000 times more luminous than the Sun. On average, it has an absolute magnitude of −9.5, making it one of the visually brightest stars known. Its surface diameter measures 450 times that of the Sun, or approximately 630,000,000 kilometers. As a yellow hypergiant it is one of the rarest types of stars. Although only around a dozen are known in the Milky Way it is not the only one in its constellation, which also includes V509 Cassiopeiae. Rho Cassiopeiae is a single star, and is categorized as a semiregular variable.>>

rstevenson wrote:Didn't I read, probably somewhere here on the Asterisk, that every star we can see with the naked eye is within about 55 ly of Sol?

Ron-Astro Pharmacist wrote:
Picture has a Yin – Yang characteristic. Artistic Intention? Maybe it’s universal to our galactic environment.

rstevenson wrote:Didn't I read, probably somewhere here on the Asterisk, that every star we can see with the naked eye is within about 55 ly of Sol?

Rob

neufer wrote:

Ron-Astro Pharmacist wrote:
Picture has a Yin – Yang characteristic. Artistic Intention? Maybe it’s universal to our galactic environment.

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[b][color=#0000FF]Cosmic microwave background radiation temperature dipole variation (and the Milky Way Galaxy). The smooth variation between relatively hot (upper right) and relatively cold (lower left) areas is due to the motion of the solar system relative to distant matter in the universe. The signals attributed to this variation are very small, only one thousandth the brightness of the sky.[/color][/b]

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rstevenson wrote:Didn't I read, probably somewhere here on the Asterisk, that every star we can see with the naked eye is within about 55 ly of Sol?

Rob

Anthony Barreiro wrote:

rstevenson wrote:Didn't I read, probably somewhere here on the Asterisk, that every star we can see with the naked eye is within about 55 ly of Sol?

Rob

My rule of thumb is that almost all the individual stars we can see with our unaided eyes are tens to hundreds of light years distant. There are a few stars closer than 10 light years, and a few very bright stars visible over thousands of light years.

http://en.wikipedia.org/wiki/List_of_mo ... nous_stars wrote:
It may also interest the reader to know that the Sun is more luminous than approximately 95% of all known stars in the local neighborhood (out to, say, a few hundred light years), due to enormous numbers of somewhat less massive stars that are cooler and often much less luminous.

Ken Crosswell wrote in his book Planet Quest First Harvest Edition 1998, chapter 5, page 78:
Incredibly, 99 percent of the stars visible to the naked eye outshine the Sun, yet 95 percent of all stars that exist actually emit less light than the Sun.

Chris Peterson wrote:

kchoekstra wrote:Question! Is this how the human eye sees it or have the photos been enhanced? If this is actual I would so want to experience this view.

Our eyes are not sensitive enough to see the view this way. Visually, the sky would appear nearly black, with a slight gray background glow, just a little brighter around the airglow and above the towns. The Milky Way looks the same there as it does from any dark site: a gray band across the sky. The only evident color would be the subtle range of warm whites to pale blues that stars show.

Jim W wrote:Nice photo! Is the arch in the Milky Way caused by the camera lens, or does it really arch that way? If it actually arches, please explain why we see it that way when the Milky Way disk apparently is flat.

Anthony Barreiro wrote:Remember that this is a panoramic photo, and imagine that you are looking to the south-southwest as you look toward the left edge of the image. Now imagine that you are both turning toward the north-northeast (toward your right), and looking first higher in the sky and then down toward the north-northeast horizon as you follow the milky way across the rest of the image. In real life the milky way would arch high across the sky from the south-southwest horizon to the north-northeast horizon, passing nearly straight overhead.

Nitpicker wrote:

Anthony Barreiro wrote:Remember that this is a panoramic photo, and imagine that you are looking to the south-southwest as you look toward the left edge of the image. Now imagine that you are both turning toward the north-northeast (toward your right), and looking first higher in the sky and then down toward the north-northeast horizon as you follow the milky way across the rest of the image. In real life the milky way would arch high across the sky from the south-southwest horizon to the north-northeast horizon, passing nearly straight overhead.

Slight correction ... the left of the image is SSE and the galactic arch spans from SSW, through W, to NNE. The galactic arch would have been directly overhead during the day, an hour or so before the sunset. But after sunset, we see it lower in the sky, with a little less than half the galactic plane showing in this APOD.

rstevenson wrote:Didn't I read, probably somewhere here on the Asterisk, that every star we can see with the naked eye is within about 55 ly of Sol?

rstevenson wrote:

rstevenson wrote:Didn't I read, probably somewhere here on the Asterisk, that every star we can see with the naked eye is within about 55 ly of Sol?

I wonder what it was that I thought I was remembering?

Rob

Nitpicker wrote:

rstevenson wrote:

rstevenson wrote:Didn't I read, probably somewhere here on the Asterisk, that every star we can see with the naked eye is within about 55 ly of Sol?

I wonder what it was that I thought I was remembering?

Sol, with an absolute magnitude of 4.83, would be at the limit of naked eye visibility (apparent magnitude 6.0) if it were 55 light years away.

Anthony Barreiro wrote:

Nitpicker wrote:

Anthony Barreiro wrote:Remember that this is a panoramic photo, and imagine that you are looking to the south-southwest as you look toward the left edge of the image. Now imagine that you are both turning toward the north-northeast (toward your right), and looking first higher in the sky and then down toward the north-northeast horizon as you follow the milky way across the rest of the image. In real life the milky way would arch high across the sky from the south-southwest horizon to the north-northeast horizon, passing nearly straight overhead.

Slight correction ... the left of the image is SSE and the galactic arch spans from SSW, through W, to NNE. The galactic arch would have been directly overhead during the day, an hour or so before the sunset. But after sunset, we see it lower in the sky, with a little less than half the galactic plane showing in this APOD.

Thanks. You have the advantage of actually having seen this part of the sky. I'm looking at planetarium software and mentally translating. The sky is seaish, computer screens are riverish.