Comments on: The Unaided Eye http://science.kqed.org/quest/2007/09/28/the-unaided-eye/ Explore science, nature and environment stories from Northern California and beyond with KQED’s multimedia series Thu, 24 May 2012 05:51:00 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Ben Burress http://science.kqed.org/quest/2007/09/28/the-unaided-eye/#comment-14880 Ben Burress Wed, 14 Sep 2011 20:19:55 +0000 http://www.kqed.org/quest/blog/2007/09/28/the-unaided-eye/#comment-14880 Well I THOUGHT I included the link! Let's try that again: http://www.badastronomy.com/qandba/transcript_episode3.html :) Well I THOUGHT I included the link! Let's try that again:
http://www.badastronomy.com/qandba/transcript_episode3.html

:)

]]> By: Dale Sanderson http://science.kqed.org/quest/2007/09/28/the-unaided-eye/#comment-14879 Dale Sanderson Wed, 14 Sep 2011 20:05:14 +0000 http://www.kqed.org/quest/blog/2007/09/28/the-unaided-eye/#comment-14879 Thanks so much for your quick response. Maybe I'm being daft, but I didn't see a link to Phil's article. I searched his blog, but don't think I found the article to which you referred. Regardless, I think the gist of your article is still correct, namely: with very few exceptions, what we can see from Earth with the unaided eye "is comprised of about 9000 stars ranging in distance from 4 to 4000 light years". I read elsewhere that the next-nearest spiral arm (the Perseus Arm) is over 6000 LY distant, so I think that means another way of looking at it is: the vast majority of what's visible to the unaided eye is not only within the Milky Way Galaxy, but within our own Local Spur of the galaxy. Thanks so much for your quick response. Maybe I'm being daft, but I didn't see a link to Phil's article. I searched his blog, but don't think I found the article to which you referred. Regardless, I think the gist of your article is still correct, namely: with very few exceptions, what we can see from Earth with the unaided eye "is comprised of about 9000 stars ranging in distance from 4 to 4000 light years". I read elsewhere that the next-nearest spiral arm (the Perseus Arm) is over 6000 LY distant, so I think that means another way of looking at it is: the vast majority of what's visible to the unaided eye is not only within the Milky Way Galaxy, but within our own Local Spur of the galaxy.

]]> By: Ben Burress http://science.kqed.org/quest/2007/09/28/the-unaided-eye/#comment-14874 Ben Burress Wed, 14 Sep 2011 15:37:28 +0000 http://www.kqed.org/quest/blog/2007/09/28/the-unaided-eye/#comment-14874 Yes, I am still listening! :) Thanks for the question, Dale. And on reviewing my own blog, I found an error in my original numbers...but also, in checking on the facts, I've found a number of other blogs and articles that have slightly different answers to the question, "what's the farthest star visible to the unaided eye?" Below is a link to one of these--Phil Plait's Bad Astronomy page--that's worth a read. As for the correction, I think I was mixing two different sources of info. The star I was referring to in Cassiopeia is Rho Cassiopeia--which, in fact, is approximately 12000 light years away. I've also seen different values for its luminosity, everything from 100,000 times the Sun's to 550,000 times. At any rate, it is visible to the unaided eye, and it's a good deal farther away than 4000 light years. Another blog I ran across hold up another star in Cass, Hipparcos 5926, as being over 16,000 light years away, and still naked-eye visible. Here's an enhanced answer to your question, though. Rho Cass is at least a singular example of a naked eye star that is quite distant, at 12,000 light years, which is almost half the distance from Earth to the center of the Milky Way Galaxy (we're about 27,000 light years from there), which is a healthy distance into the galaxy by any stretch. The "glow" of the Milky Way, which comes from massed distant stars that we don't see as individuals with our eyes, comes, I believe, from a greater distance...but of course when you look at it, you're not looking at singular object. Phil's article also mentions that people with really good eyesight under extremely good viewing conditions can see the galaxy M81, which is 12 million light years away...beating even the Andromeda by quite a bit. Well, I hope that helps! Yes, I am still listening! :) Thanks for the question, Dale. And on reviewing my own blog, I found an error in my original numbers…but also, in checking on the facts, I've found a number of other blogs and articles that have slightly different answers to the question, "what's the farthest star visible to the unaided eye?" Below is a link to one of these–Phil Plait's Bad Astronomy page–that's worth a read.

As for the correction, I think I was mixing two different sources of info. The star I was referring to in Cassiopeia is Rho Cassiopeia–which, in fact, is approximately 12000 light years away. I've also seen different values for its luminosity, everything from 100,000 times the Sun's to 550,000 times. At any rate, it is visible to the unaided eye, and it's a good deal farther away than 4000 light years.

Another blog I ran across hold up another star in Cass, Hipparcos 5926, as being over 16,000 light years away, and still naked-eye visible.

Here's an enhanced answer to your question, though. Rho Cass is at least a singular example of a naked eye star that is quite distant, at 12,000 light years, which is almost half the distance from Earth to the center of the Milky Way Galaxy (we're about 27,000 light years from there), which is a healthy distance into the galaxy by any stretch. The "glow" of the Milky Way, which comes from massed distant stars that we don't see as individuals with our eyes, comes, I believe, from a greater distance…but of course when you look at it, you're not looking at singular object.

Phil's article also mentions that people with really good eyesight under extremely good viewing conditions can see the galaxy M81, which is 12 million light years away…beating even the Andromeda by quite a bit.

Well, I hope that helps!

]]> By: Dale Sanderson http://science.kqed.org/quest/2007/09/28/the-unaided-eye/#comment-14858 Dale Sanderson Tue, 13 Sep 2011 21:03:24 +0000 http://www.kqed.org/quest/blog/2007/09/28/the-unaided-eye/#comment-14858 I realize this article was written quite some time ago... I hope you're still listening. I'm wondering if the unaided eye can observe anything (besides the handful of unaided-eye galaxies) that lies outside of the Orion Arm (or Local Spur) of our galaxy. This article comes closer to answering the question than any other I've found... but to which star in Cassiopeia are you referring? I read elsewhere that Rho Cas is nearly 12,000 ly away... true? Thanks... I realize this article was written quite some time ago… I hope you're still listening. I'm wondering if the unaided eye can observe anything (besides the handful of unaided-eye galaxies) that lies outside of the Orion Arm (or Local Spur) of our galaxy. This article comes closer to answering the question than any other I've found… but to which star in Cassiopeia are you referring? I read elsewhere that Rho Cas is nearly 12,000 ly away… true? Thanks…

]]> By: Jon Swartz http://science.kqed.org/quest/2007/09/28/the-unaided-eye/#comment-10950 Jon Swartz Thu, 19 Nov 2009 03:27:49 +0000 http://www.kqed.org/quest/blog/2007/09/28/the-unaided-eye/#comment-10950 Great explanation... exactly what I was looking for -thanks! Great explanation… exactly what I was looking for -thanks!

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