chatoyancy

[neufer]

http://antwrp.gsfc.nasa.gov/apod/ap080322.html
http://antwrp.gsfc.nasa.gov/apod/ap990916.html
http://antwrp.gsfc.nasa.gov/apod/ap070629.html
http://antwrp.gsfc.nasa.gov/apod/ap031101.html
http://antwrp.gsfc.nasa.gov/apod/ap010111.html



<<In gemology, chatoyancy (or chatoyance) is an optical reflectance effect seen in certain gemstones. Coined from the French "oeil de chat", meaning "cat's eye", chatoyancy arises either from the fibrous structure of a material, as in tiger eye quartz, or from fibrous inclusions or cavities within the stone, as in cat's eye chrysoberyl. The effect can be likened to the sheen off a spool of silk: the luminous streak of reflected light is always perpendicular to the direction of the fibres. For a gemstone to show this effect best it must be cut en cabochon, with the fibers or fibrous structures parallel to the base of the finished stone. Faceted stones are less likely to show the effect well. Gem species known for this phenomenon include the aforementioned quartz, chrysoberyl, beryl (especially var. aquamarine), tourmaline, apatite, moonstone and scapolite.>> - Wikipedia

<<A cat's vision is superior at night in comparison to humans, and inferior in daylight. Cats, like dogs and many other animals, have a tapetum lucidum, which is a reflective layer behind the retina that reflects light that passes through the retina back into the eye. While this enhances the ability to see in low light, it appears to reduce net visual acuity, thus detracting when light is abundant. In very bright light, the slit-like iris closes very narrowly over the eye, reducing the amount of light on the sensitive retina, and improving depth of field. The tapetum and other mechanisms give the cat a minimum light detection threshold up to seven times lower than that of humans. Variation in color of cats' eyes in flash photographs is largely due to the reflection of the flash by the tapetum.>> - Wikipedia

[NoelC]

I must say, neufer, that while I will be the first to admit that "thinking outside the box" is a great thing in many instances, I'm having some trouble understanding how there's any connection at all between the material ejected at the end of a star's life and the composition of gemstones or the vision of a cat beyond just the name of the object.

Someone, probably with a telescope and/or imaging system inferior to today's better hardware, named it the "Cat's Eye Nebula" no doubt because it looked vaguely like an eye with a slit in it.

Nocturnal folks somewhere in the dim past also named asterisms after animals and characters in their imaginations, and the constellation names today serve to help us know where they are in a grand sense... Frankly the only constellation that ever remotely resembled what it's called to me is Orion, and only then because of the "belt" and "sword". Okay, so they didn't have television nor light pollution - an enviable condition - but does this mean there's some mystical connection up there? I think not. "Dipper" I can get, but "Great Bear"? Nope.

Is there a deeper point I'm missing to your "cat's eye" connection here?

-Noel

[henk21cm]

Frankly the only constellation that ever remotely resembled what it's called to me is Orion

[smile]The obvious constellation that resembles what it is supposed to be, is the triangle, (Triangulum) that -indeed- looks like a triangle. [/smile]

[bystander]

The obvious constellation that resembles what it is supposed to be, is the triangle, (Triangulum) that -indeed- looks like a triangle.

For the longest time, I couldn't see why M33 was called the Triangulum Galaxy. The Great Pinwheel Galaxy I could understand. But then, the light appeared, M33 is next to that well known Triangulum Constellation.

[neufer]

I must say, neufer, that while I will be the first to admit that "thinking outside the box" is a great thing in many instances, I'm having some trouble understanding how there's any connection at all between the material ejected at the end of a star's life and the composition of gemstones or the vision of a cat beyond just the name of the object.

Someone, probably with a telescope and/or imaging system inferior to today's better hardware, named it the "Cat's Eye Nebula" no doubt because it looked vaguely like an eye with a slit in it.

Is there a deeper point I'm missing to your "cat's eye" connection here? -Noel

I just wanted to CHAT AWAY about CHAToyancy, Noel:
---------------------------------------------

• Dedication : The Hunting of the SNARK (An Agony in Eight Fits) [1876]
  
  [G I R T] with a boyish garb for boyish task,
  [E]ager she wields her SPADE; yet loves as well
  est on a friendly knee, intent to ask
  [T]he tale he loves to tell.
  
  [R U D E] spirits of the seething outer strife,
  nmeet to read her pure and simple spright,
  [D]eem, if you list, such hours a WASTE of life,
  [E]mpty of all delight!
  
  , sweet Maid, and rescue from ANNOY
  [H]earts that by wiser talk are unbeguiled.
  [A]h, happy he who owns that tenderest JOY ,
  [T]he heart-love of a child!
  
  [A W A Y], fond thoughts, and vex my soul no more!
  [W]ork claims my wakeful nights, my busy days--
  [A]lbeit bright memories of that sunlit shore
  [Y]et haunt my dreaming gaze!

<<Lewis Carroll first met GERTRUDE CHATAWAY on the beach at Sandown.
She was perhaps his greatest child-love after ALICE Liddell.>>
http://www.geocities.com/transrescen/fbp/carroll.html
----------------------------------------------------

Nocturnal folks somewhere in the dim past also named asterisms after animals and characters in their imaginations, and the constellation names today serve to help us know where they are in a grand sense... Frankly the only constellation that ever remotely resembled what it's called to me is Orion, and only then because of the "belt" and "sword".

http://www.science-teachers.com/space/C ... Cards1.jpg
http://www.science-teachers.com/space/C ... Cards2.jpg
http://www.science-teachers.com/space/C ... Cards3.jpg
http://www.science-teachers.com/space/C ... Cards4.jpg
http://www.science-teachers.com/space/C ... Cards5.jpg
http://www.science-teachers.com/space/C ... Cards6.jpg
http://www.science-teachers.com/space/C ... Cards7.jpg
-----------------------------------------------------

• 
  The Hunting of the SNARK (An Agony in Eight Fits) [1876]
  
  The last of the crew needs especial remark,
  Though he looked an incredible dunce:
  He had just one idea -- but, that one being "Snark,"
  The good Bellman engaged him at once.
  
  He came as a BUTCHER: but gravely declared,
  When the ship had been sailing a week,
  He could only kill beavers. The Bellman looked scared,
  And was almost too frightened to speak:

Maybe it's just my imagination but the Snark Hunting
BUTCHER ("an incredible dunce") remotely resembles
Alfred E. Neuman.

[bystander]

I must say, neufer, that while I will be the first to admit that "thinking outside the box" is a great thing in many instances, I'm having some trouble understanding how there's any connection at all between the material ejected at the end of a star's life and the composition of gemstones or the vision of a cat beyond just the name of the object.

...

Is there a deeper point I'm missing to your "cat's eye" connection here?

I sometimes think that neufer is trying to impress us with the vast amount of time he has to waste looking up trivial references and copying the text to this forum. Must be a lack of things to do when you are a retired physicist. I don't always see the relavancy in all of his posts, either.

No offense, neufer, but I think all would be better served if you posted the links (Chatoyancy, and Cat's vision) and providing the relavancy in your post so the rest of us don't get lost.

Plus, when you post those big pictures, it messes up the scrolling.

[neufer]

I sometimes think that neufer is trying to impress us with the vast amount of time he has to waste looking up trivial references and copying the text to this forum. Must be a lack of things to do when you are a retired physicist. I don't always see the relavancy in all of his posts, either.

No offense, neufer, but I think all would be better served if you posted the links (Chatoyancy, and Cat's vision) and providing the relavancy in your post so the rest of us don't get lost.

Possibly.

But don't you feel that you are somehow a better person
now that "chatoyancy" is part of your everyday vocabulary?
-----------------------------------------
Even us bored retired physicists have to relieve themselves from time to time:

• ....................................................
  Relevant, a. [F. relevant, p. pr. of relever to raise again, to relieve.]
  
  1. Relieving; lending aid or support.
  
  2. Bearing upon, or properly applying to, the case in hand; pertinent; applicable.
  ....................................................
  Relative, a. [F. relatif, L. relativus.]
  
  1. Having relation or reference; referring; respecting; standing in connection; pertaining; as, arguments not relative to the subject.
  
  2. Arising from relation; resulting from connection with, or reference to, something else; not absolute.

-----------------------------
And, at least, I'm not as opaque & repetitious as some :

http://antwrp.gsfc.nasa.gov/apod/ap080323.html
http://antwrp.gsfc.nasa.gov/apod/ap060409.html
http://antwrp.gsfc.nasa.gov/apod/ap041219.html
http://antwrp.gsfc.nasa.gov/apod/ap030202.html
http://antwrp.gsfc.nasa.gov/apod/ap010923.html
http://antwrp.gsfc.nasa.gov/apod/ap990511.html

[Arramon]

LOL... that's funny. The images going back in time just got smaller and smaller. =b

hehehhe... good ol' image processing programs to the rescue!

[Arramon]

Barnard 68:
news.bbc.co.uk/1/hi/sci/tech/334738.stm

But what is this???


its magical...


but wait! through the greatness of newer and more advanced technology, we have come to identify the true nature of this giant hole in the universe!

http://www.10thcircle.com/10/wp-content ... um_bc2.JPG

[bystander]

Possibly.

But don't you feel that you are somehow a better person
now that "chatoyancy" is part of your everyday vocabulary?
-----------------------------------------
Even us bored retired physicists have to relieve themselves from time to time:
-----------------------------
And, at least, I'm not as opaque & repetitious as some

I'm sure I'll find many occasion in which to use the word. As to whether that makes me a better person???? 8)

Please feel free to relieve yourself anytime, just allow me time to get out of the way.

Opaque? I don't know. Maybe 1 thru 3 apply sometimes, but never 4.

• opaque (comparative more opaque, superlative most opaque)
  
  From Latin opacus (“‘shaded, shady, dark’”), itself of unknown origin, originally spelled opake, and in the 17th century respelled after the cognate French opaque.
  
  • 1. Neither reflecting nor emitting light.
    2. Allowing little light to pass through, not translucent or transparent.
    3. (metaphor) Unclear, unintelligible, hard to get or explain the meaning of
    4. (metaphor) Obtuse, stupid.

Maybe oblique (not straightforward; indirect; obscure; hence, disingenuous; underhand; perverse; sinister) is better.

[ChrisO]

Frankly the only constellation that ever remotely resembled what it's called to me is Orion

[smile]The obvious constellation that resembles what it is supposed to be, is the triangle, (Triangulum) that -indeed- looks like a triangle. [/smile]

So... it's Orion vs. Triangulum... Orion, great constellation, pretty good name. Triangulum, user-friendly constellation, but much better name. I say that Triangulum beats the pants off of Orion! Oh wait, Orion isn't wearing any pants, now if we could only find the Orion Pants Nebula...

-Chris O

[makc]

http://antwrp.gsfc.nasa.gov/apod/ap990916.html

and there we read:

this nebula's detectable shift over a three year period allows the expansion age of its bright inner shells to be estimated at only around 1,000 years while its distance can be gauged at about 3,000 light-years.

Interpretation?

[bystander]

http://antwrp.gsfc.nasa.gov/apod/ap990916.html

and there we read:

this nebula's detectable shift over a three year period allows the expansion age of its bright inner shells to be estimated at only around 1,000 years while its distance can be gauged at about 3,000 light-years.

Interpretation?

NGC 6543 is about 3,000 light years distant. The inner shells (over half a light year across) have been evolving for about 1,000 years. Other APOD's estimate the outer halo (over 5 light years across) is 50,000 to 90,000 years old.

http://antwrp.gsfc.nasa.gov/apod/ap070513.html
http://antwrp.gsfc.nasa.gov/apod/ap070629.html

HST studies a few years apart allow measurements of both distance and age.