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Re: APOD: Geminid Meteors over Xinglong... (2015 Dec 23)

Posted: Thu Dec 24, 2015 9:36 pm
by Ann
Chris Peterson wrote:
neufer wrote:
Click to play embedded YouTube video.
Do you see colors here? I see nothing but grays. But I have a wheel like this that I use in the classroom, and with that I see lots of colors. So again, a difference I think in how our eyes perceive things directly and how cameras capture them (in this case with the added complexity of video, so time becomes a factor, not just the sensor dynamics).
I, too, see nothing but grays.

Chris, you wrote:
But visual observers more commonly report much less saturated color, as well as a range of yellows, oranges, and reds that are not typically seen in photographs. Camera images are a poor representation of the visual experience of color.
Okay, but so what? If most really bright meteors look green or blue when photographed, then surely the colors reflect some physical properties of the meteors. Surely, in some sense, these meteors are green or blue.

My best friend's son saw a bolide some years ago. He was incredibly impressed and kept describing his experience like this: It was green!!

Ann

Re: APOD: Geminid Meteors over Xinglong... (2015 Dec 23)

Posted: Thu Dec 24, 2015 10:32 pm
by Chris Peterson
Ann wrote:Chris, you wrote:
But visual observers more commonly report much less saturated color, as well as a range of yellows, oranges, and reds that are not typically seen in photographs. Camera images are a poor representation of the visual experience of color.
Okay, but so what? If most really bright meteors look green or blue when photographed, then surely the colors reflect some physical properties of the meteors. Surely, in some sense, these meteors are green or blue.
I only brought it up to distinguish between my explanation for the colors as they appear in the image, and the AMS page which describes some physical processes and details of human vision. The latter is only of limited use in explaining the colors in the image.

Most meteors which show color are dominated by green, the result of atmospheric oxygen. But there is a range of other color possible, and the nature of how that light is produced results in sometimes very different results visually and photographically.

Re: APOD: Geminid Meteors over Xinglong... (2015 Dec 23)

Posted: Thu Dec 24, 2015 10:58 pm
by Ann
neufer wrote:
Chris Peterson wrote:
geckzilla wrote:
I get what people are trying to say by "there is no such thing as color" but I beg to differ. Color is how our brains translate certain wavelengths of EM radiation into a signal we understand.
The guy in the video is the only person I've ever heard claim that there's no such thing as color. And from the rest of his comments, it's clear that he's just saying that as a rhetorical device.
Yes, Ann, the not so terribly amazing Dr. B is wrong... there is color! Dr. B has been affected by the skepticism of a skeptical age. He does not believe what he sees. He thinks that nothing can be which is not comprehensible by his little mind. In this great universe of ours, man is a mere insect in his intellect as compared with the boundless world about him, as measured by the intelligence capable of grasping the whole of truth and knowledge. Alas! How dreary would be the world if there were no color! It would be as dreary as if there were no Anns. The eternal blue light with which childhood fills the world would be extinguished. Not believe in color! You might as well not believe in blue fairies!
:lol2:

So, Art, are you telling me, sideways... that my middle name just might be Virginia and that there really is a big old man who is only seen around December 25 every year (December 24 in Sweden) and who wears red whenever you see him?
Click to play embedded YouTube video.
Ann

Re: APOD: Geminid Meteors over Xinglong... (2015 Dec 23)

Posted: Thu Dec 24, 2015 11:00 pm
by Chris Peterson
Ann wrote:So, Art, are you telling me, sideways... that my middle name just might be Virginia and that there really is a big old man who is only seen around December 25 every year (December 24 in Sweden) and who wears red whenever you see him?
But only if you believe... really believe... that red is real.

Re: APOD: Geminid Meteors over Xinglong... (2015 Dec 23)

Posted: Fri Dec 25, 2015 6:49 am
by Ann
Chris Peterson wrote:
Ann wrote:So, Art, are you telling me, sideways... that my middle name just might be Virginia and that there really is a big old man who is only seen around December 25 every year (December 24 in Sweden) and who wears red whenever you see him?
But only if you believe... really believe... that red is real.
Red? It's real?

C'mon. That's a ruddy fantasy.

Ann

Re: APOD: Geminid Meteors over Xinglong... (2015 Dec 23)

Posted: Fri Dec 25, 2015 7:52 am
by MarkBour
MarkBour wrote:Thanks, neufer, for posting the article about the LAMOST / Guo Shoujing Telescope and its mission. Sounds like some really massive datasets to be gathered. As an earth-based telescope, will its spectra be limited, or is it expected that lots of great data will be gathered here? Are Chinese astronomers likely to make their data available freely, even to the West? Will this result in a more detailed map of the stars in our galaxy, with relative motions? Are there other places that similar/competing data are being gathered that astronomers here are more interested in?
Ah. Sorry for bringing up my own note, and sorry for being so clueless on this topic. I just learned a bit about the Sloan Digital Sky Survey, which I think is well-known to most of you. Sounds like it has been gathering the same kind of data as was described as the mission for the LAMOST telescope. In fact, now I'm wondering how the data compare -- what is different about what the LAMOST project is gathering.

P.S. I got no color sensation from Benham's Wheel via youtube video. And I don't think it was skepticism that colored my perception (sorry).

P.P.S. Yes, Ann, most people think Santa wears red, and his sleigh is red too, only because they've mostly seen him flying away. I think the sleigh tops out at about 0.3c ... Santa actually prefers blue suits. Happy Christmas to all.