APOD: A Zodiacal Skyscape (2012 Feb 23)

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Expand view Topic review: APOD: A Zodiacal Skyscape (2012 Feb 23)

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by Chris Peterson » Sun Feb 26, 2012 3:23 pm

geckzilla wrote:I think I agree, I mean this quote in particular from Wikipedia makes little sense to me:
As these groupings are not human constructs, but real phenomena, they do not count as asterisms.
Wikipedia is, on the whole, a good source of information. But it isn't perfect. The statement makes no sense. Taken to its [il]logical extreme, it would suggest that there are groupings of stars that are NOT natural constructs!

AFAIK there is no formal definition of "asterism". Like most words, its definition is simply the product of usage. Astronomers use the term to refer to recognizable star groupings, that's all. Constellations are asterisms. Open clusters are asterisms. Specific groupings within clusters are asterisms. Groupings inside nebulas (e.g. the Trapezium) are asterisms. Asterisms may be big and obvious to the naked eye, like the Pleiades, or tiny telescopic objects, like M11, the Wild Duck cluster.

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by bystander » Sun Feb 26, 2012 6:07 am

TNT wrote:what's ET? Is it some sort of star cluster?
Wikipedia: NGC 457 wrote:NGC 457 (also known as the Owl Cluster, the ET Cluster, or Caldwell 13) is an open star cluster in the constellation Cassiopeia. It was discovered by William Herschel in 1787. and lies over 7,900 light years away from the Sun. It has an estimated age of 21 million years. The cluster is sometimes referred by amateur astronomers as the Owl Cluster, Kachina Doll Cluster, the ET Cluster (due to its resemblance to the movie character) or the "Skiing Cluster". Two bright stars, magnitude 5 Phi-1 Cassiopeiae and magnitude 7 Phi-2 Cassiopeiae can be imagined as eyes. The cluster features a rich field of about 150 stars of magnitudes 12-15.

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by geckzilla » Sun Feb 26, 2012 6:01 am

Chris Peterson wrote:
Ann wrote:Now wait a minute... the Pleiades is an asterism :?: :?: :?: :?:

I don't think so :!: :!: :!:
It absolutely is an asterism! Many people mistake it for the Little Dipper. An asterism is a recognizable pattern of stars, nothing else. Any open cluster that has that feature (like the Pleiades, Coathanger, or ET) is perfectly reasonably called an asterism.
I think I agree, I mean this quote in particular from Wikipedia makes little sense to me:
As these groupings are not human constructs, but real phenomena, they do not count as asterisms.
What this means is that just because they really are close together means they can't be an asterism? There's a lack of citations on that section of Wikipedia and it seems odd to restrict the labeling of something to just one thing. Can open clusters not also form distinct asterisms? But then again I see this argument taking the same path as the Pluto planet status argument.

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by TNT » Sun Feb 26, 2012 5:37 am

Chris, what's ET? Is it some sort of star cluster?

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by Beyond » Sun Feb 26, 2012 4:01 am

Little Dipper?? I've always called it a scoop. That is, until i got the 'scoop' on it. :mrgreen:

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by Chris Peterson » Sun Feb 26, 2012 3:42 am

Ann wrote:Now wait a minute... the Pleiades is an asterism :?: :?: :?: :?:

I don't think so :!: :!: :!:
It absolutely is an asterism! Many people mistake it for the Little Dipper. An asterism is a recognizable pattern of stars, nothing else. Any open cluster that has that feature (like the Pleiades, Coathanger, or ET) is perfectly reasonably called an asterism.

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by geckzilla » Sun Feb 26, 2012 12:34 am

Ann wrote:Now wait a minute... the Pleiades is an asterism :?: :?: :?: :?:

I don't think so :!: :!: :!:

Ann
I just refreshed my memory on the definition of an asterism and I don't see why the Pleiades shouldn't qualify.

Edit: Although, further reading on Wikipedia reveals this:
http://en.wikipedia.org/wiki/Asterism_( ... -asterisms
Open clusters are groups of stars that are physically related — gravitationally bound together and moving through the galaxy in the same direction and speed. As these groupings are not human constructs, but real phenomena, they do not count as asterisms. Among the best-known and closest are the Pleiades (M45) and the Hyades in Taurus and the Beehive (M44) in Cancer. (It may be noted that, with the addition of Aldebaran, which is in the same line of sight, the Hyades open cluster forms a V-shaped sectional asterism in Taurus).

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by DavidLeodis » Sat Feb 25, 2012 7:13 pm

I've noticed that in the copy of the explanation to the APOD given on page 1 it uses 'Pleiades' but, currently at least, it still uses 'Pleides' in the explanation to the APOD as it was issued. :)

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by Ann » Sat Feb 25, 2012 7:00 pm

Chris Peterson wrote:
jackfusco wrote:I've actually seen it spelled Pleiades more often than Pleiads. For what it's worth, the spell check on Chrome marks Pleiads incorrect.
The question was with respect to the spelling "Pleides", which is simply incorrect.

The asterism is named for the mythical seven sisters, the Pleiades. Singularly, they are called "Pleiads", so that spelling is correct so long as you are referring to the individual sisters, or to individual stars, and not to the asterism itself.
Now wait a minute... the Pleiades is an asterism :?: :?: :?: :?:

I don't think so :!: :!: :!:

Ann

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by Beyond » Sat Feb 25, 2012 6:50 pm

Chris Peterson wrote:
Beyond wrote:Now wait a minute, a single star from the Pleiades is called a Pleiads? That seems to be plural to me. You sure a single star is not called a Pleiad? :?
Singularly they are called Pleiads. One is called a Pleiad. So the spelling "Pleiads" is correct for the case I gave- referring to the stars (plural).
Ok, lets see if i got this right. Pleiades is the whole thing, of which the seven sisters are part. Each sister is a Pleiad. If you are referring to more than one sister at a time, then they are called Pleiads, because you are referring to more than one one. I-Pleiad + 1-Pleiad = 2-Pleiads.
Ok, it wasn't the math, it was the english.

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by Beyond » Sat Feb 25, 2012 6:39 pm

Neufer, i would say that you have stretched Art about as far as Art can go, in the Asterisk*. :yes:

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by neufer » Sat Feb 25, 2012 5:03 pm

Beyond wrote:
Now wait a minute, a single star from the Pleiades is called a Pleiads?
That seems to be plural to me. You sure a single star is not called a Pleiad? :?
http://en.wikipedia.org/wiki/Pleiades_in_folklore_and_literature wrote: <<The Lakota Tribe of North America had a legend that linked the origin of the Pleiades to Devils Tower. According to the Seris (of northwestern Mexico), these stars are seven women who are giving birth. The constellation is known as Cmaamc, which is apparently an archaic plural of the noun cmaam "woman".

In a Blackfoot legend, the Pleiades are orphans ("Lost Boys") :arrow:
that were not cared for by the people, so they became stars. Sun Man is angered by the mistreatment of the children and punishes the people with a drought, causing the buffalo to disappear, until the dogs, the only friends of the orphans, intercede on behalf of the people. Because the buffalo are not available while the Lost Boys are in the skies, the cosmical setting of the Pleaides was an assembly signal for Blackfoot hunter to travel to their hunting grounds to conduct the large-scale hunts, culminating in slaughters at buffalo jumps.

The Hopi built their underground kivas for multiple utilitarian uses, the most important of which was a ceremonial meeting place. Access was through a ladder in a small hole in the roof of the kiva, and during certain ceremonies, the night passage of the Pleiades over the center of the opening was a direct signal to begin a certain ceremony. Most of the cultures used the angle of the Pleiades in the night sky as a time telling device.

A Cheyenne myth "The Girl Who Married a Dog", states that the group of seven stars known as the Pleiades originated from seven puppies which a Cheyenne chief's daughter gave birth to after mysteriously being visited by a dog in human form to whom she vowed "Wherever you go, I go".

The Shasta people tell a story of the children of racoon killed by coyote avenging their father's death and then rising into the sky to form the Pleiades. The smallest star in the cluster is said to be coyote's youngest who aided the young racoons.

The Onondaga people's version of the story has lazy children who prefer to dance over their daily chores ingnoring the warnings of the Bright Shining Old Man. The Monache people tell of 6 wives who loved onions more than their husbands and now live happily in "sky country". The early Monte Alto Culture and others in Guatemala such as Ujuxte and Takalik Abaj, made its early observatories, using the Pleiades and Eta Draconis as reference, they were called the seven sisters, and thought to be their original land. In the ancient Andes, the Pleiades were associated with abundance, because they return to the Southern Hemisphere sky each year at harvest-time. In Quechua they are called collca' (storehouse). The ancient Aztecs of Mexico and Central America based their calendar upon the Pleiades. Their year began when priests first remarked the asterism heliacal rising in the east, immediately before the sun's dawn light obliterated the view of the stars. Aztecs called the Pleiades Tianquiztli (meaning "marketplace").>>

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by Chris Peterson » Sat Feb 25, 2012 4:54 pm

Beyond wrote:Now wait a minute, a single star from the Pleiades is called a Pleiads? That seems to be plural to me. You sure a single star is not called a Pleiad? :?
Singularly they are called Pleiads. One is called a Pleiad. So the spelling "Pleiads" is correct for the case I gave- referring to the stars (plural).

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by Beyond » Sat Feb 25, 2012 4:45 pm

Now wait a minute, a single star from the Pleiades is called a Pleiads? That seems to be plural to me. You sure a single star is not called a Pleiad? :?

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by neufer » Sat Feb 25, 2012 4:24 pm

Click to play embedded YouTube video.
Chris Peterson wrote:
jackfusco wrote:
I've actually seen it spelled Pleiades more often than Pleiads. For what it's worth, the spell check on Chrome marks Pleiads incorrect.
The question was with respect to the spelling "Pleides", which is simply incorrect.

The asterism is named for the mythical seven sisters, the Pleiades. Singularly, they are called "Pleiads", so that spelling is correct so long as you are referring to the individual sisters, or to individual stars, and not to the asterism itself.

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by Chris Peterson » Sat Feb 25, 2012 3:21 pm

jackfusco wrote:I've actually seen it spelled Pleiades more often than Pleiads. For what it's worth, the spell check on Chrome marks Pleiads incorrect.
The question was with respect to the spelling "Pleides", which is simply incorrect.

The asterism is named for the mythical seven sisters, the Pleiades. Singularly, they are called "Pleiads", so that spelling is correct so long as you are referring to the individual sisters, or to individual stars, and not to the asterism itself.

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by jackfusco » Sat Feb 25, 2012 3:09 pm

I've actually seen it spelled Pleiades more often than Pleiads. For what it's worth, the spell check on Chrome marks Pleiads incorrect.

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by DavidLeodis » Sat Feb 25, 2012 10:40 am

Cheers geckzilla. I thought that was what it might be but I did wonder. Pleiades is not an easy name to spell. :)

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by geckzilla » Sat Feb 25, 2012 1:55 am

I think it's just a common typographical error.

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by DavidLeodis » Fri Feb 24, 2012 11:29 pm

I've noticed that in the explanation it uses Pleides. I have also very occasionally seen that spelling elsewhere. I wonder therefore if Pleides is an accepted alternative spelling of the much more commonly used Pleiades. :?:

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by bystander » Fri Feb 24, 2012 8:51 pm

biljofila wrote:Hi I am interested if anyone posted picture of Mercur that is now possible to be seen in the east Europe. Tnx!
http://messenger.jhuapl.edu/gallery/sci ... llery_id=2

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by biljofila » Fri Feb 24, 2012 8:19 pm

Hi I am interested if anyone posted picture of Mercur that is now possible to be seen in the east Europe. Tnx!

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by jackfusco » Fri Feb 24, 2012 7:56 pm

TNT wrote:Great job, Jack! And congratulations for your second APOD! :ssmile:
Thank you! Needless to say, I was very excited.

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by TNT » Fri Feb 24, 2012 4:22 am

Great job, Jack! And congratulations for your second APOD! :ssmile:

Re: APOD: A Zodiacal Skyscape (2012 Feb 23)

by jackfusco » Fri Feb 24, 2012 2:07 am

Thank you everyone! I've said online already, but it's really an honor to have a second photo on APOD.That night in Cherry Springs was really incredible and I can't wait to go back. It made the 12 hours in the car well worth it. I wasn't positive if the trail near Pleiades was a meteor or from a satellite. I checked back on a few apps and didn't see anything show up for satellites that would be passing by at the time it was taken.

I think my next trip might actually be out to Spruce Knob in West Virginia. Has anyone here been there before? It's about an hour longer of a drive, but from what I hear it's a good deal better than even Cherry Springs.

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