Talk:Extinction (astronomy)

message: I wish for others to review the inclusion of Trumpler and the ref to the page and get a consensus for leaving it or excluding it.Jobberone (talk) 19:28, 10 September 2008 (UTC)
thread_title: Split

message: I've started updating and expanding this page to be more comprehensive and include more references.  This is part of a larger effort on my part to improve the information on interstellar dust in general.  Feel free to add questions to this page and/or send them my way.
Karl D. Gordon 14:32, 27 December 2006 (UTC)
thread_title: Split

message: I propose that this article is split into two pieces.  The majority of the text would go into interstellar extinction and the remaining into atmospheric extinction.  This would make more sense as the two sources of extinction arise from different physical processes.  And it would make it easier to revise both pieces to be more comprehensive.
Karl D. Gordon 16:50, 27 December 2006 (UTC)
thread_title: Split

message: The mention of the ROSAT study, and only that study, for the determination of the relationship between N(H) and A_V seems to imply that it is the definitive, if not the only, measurement.  Perhaps the Bohlin, Savage, & Drake (1978) reference should be stated, and the ROSAT study, amongst others, could be used to strengthen the confidence in the value. AmberRobot 17:51, 28 December 2006 (UTC)
replies: text: The references Bohlin/Savage/Drake(1978), Diplas/Savage(1994) and Predehl/Schmitt(1995) all give different values of differing extinctions for differing wavelengths, f.ex. Predehl/Schmitt(1995) measures in X-rays, Diplas/Savage(1994) in HI, and Bohlin/Savage/Drake(1978) sums up HI and neutral H2. The value in the text seems to give an unnecessarily rounded value for the X-ray measurement, while Bohlin/Savage/Drake(1978) gives 5.8 (not 1.8) ·1021atoms per magnitude. ... said: Rursus (bork²) 13:25, 18 June 2009 (UTC)
thread_title: N(H) vs. A_V

message: :The references Bohlin/Savage/Drake(1978), Diplas/Savage(1994) and Predehl/Schmitt(1995) all give different values of differing extinctions for differing wavelengths, f.ex. Predehl/Schmitt(1995) measures in X-rays, Diplas/Savage(1994) in HI, and Bohlin/Savage/Drake(1978) sums up HI and neutral H2. The value in the text seems to give an unnecessarily rounded value for the X-ray measurement, while Bohlin/Savage/Drake(1978) gives 5.8 (not 1.8) ·1021atoms per magnitude. ... said: Rursus (bork²) 13:25, 18 June 2009 (UTC)
thread_title: Dubious

message: It is not written how significant is the space extinction phenomenon. It should be somehow compared with other stuff. The only explanation is 0.7 mag/Kpc. Doesn't tell me anything. It should be noted whether for some star the effect can be seen by the eye, not by a curve (does the color of the star change?). Compare with redshift, and compare atmospheric vs space extinction. Setreset (talk) 06:06, 25 August 2010 (UTC)
thread_title:  magnitude unclear 

message: Hydrogen atoms per square centimeter column... I don't understand this. Does it mean a square centimeter column extending from the earth to the object being looked at? At any rate, other non-astronomers might benefit from this being made explicit.
68.186.166.197 (talk) 21:41, 24 March 2011 (UTC)
replies: text: It's the path integral of the number density along the line-of-sight between the observer and the source. Number density has units of cm^-3, whilst path length has units of cm. Mutliply the two together and you get cm^-2. This is called the 'column density'. Modest Genius talk 19:45, 26 May 2011 (UTC)
thread_title:  Atoms / cm^-2 

message: I suppose one good thing that came from the recent erroneous changes to this page is that I've reworked it.  The intro and first section should be much more readable now, and the "Technical" flag can hopefully be removed.  I don't have a cite for the "0.7-1.0 mag/kpc" typical reddening in the stellar neighborhood value, so if someone could add that, it'd be great.  Interstellar dust is not my area of expertise, so I haven't tried to update any references to reflect more recent literature, sorry. - Parejkoj (talk) 01:17, 24 May 2011 (UTC)
thread_title:  Updates - can we remove the Technical flag now? 

message: Theres a picture that can be downloaded here. I tried to get it in the article but couldn't. Perhaps someone more technical than me might like to. Orphadeus (talk) 21:42, 28 May 2011 (UTC)
replies: text: Its not just an issue of Wiki-coding but copyright.Ian.thomson (talk) 14:32, 29 May 2011 (UTC)
replies: text: Indeed. That image cannot be used under a 'free' license, nor could it qualify as fair-use. See Wikipedia:Image use policy. More to the point, it's massively out of date. Why would we want to use an image that shows very little, and that does not reflect current scientific consensus? Modest Genius talk 16:31, 29 May 2011 (UTC)
thread_title:  Anyone technical? 

message: This is getting too spread out, so I'm consolidating it:
If you are so time constrained that you cannot properly answer a number of users' points or cannot read their corrections to your constant mistakes, you should leave and focus on your life instead of wasting everyone's time.  Pretty much every editor you have interacted with has had to call you out for some sort of incompetance, and in many cases you only spat in their cases by ignoring their advice.  All the more reason you should just leave.  You are no help here.
As for your claims of "politics," Wikipedia goes with peer-reviewed journals, and books based on them.  This article at no point cites Cox or Hawking or any one else like that.  You are raising a strawman argument, a substitute for an actual point.  All the authors of the sources for this article are non-notable individuals.  Your claims of "politics" are ignorant bullshit.  Having gone to a college that tried to shove the scientific and artistic communities into the same department, the scientific community actually hates scientist celebrities, so our sources wouldn't mind knocking Hawking and Cox down a peg, if they were in the least bit relevant to this discussion.
Also, as an American, I know there's a difference between "getting funding from the government" and actually being part of the government.  Although the Lawrence Berkeley National Laboratory is funded by the US government, it's really run by the University of California.  The Wang paper is no more a document from the US government than my homework last semester.  Wang's paper looks more like homework than any peer reviewed journal article.
And I have a general message for you:
I'm an English major.  My degree is in bullshit, so I know how to spot when someone else is talking about something they don't know about.  I know you don't know what you're talking about.  You may think you do, but you do not.  Having seen you not get what an "archive" is for, I had to question your intelligence.  Having seen your complete lack of research skills and inability to form a coherent thesis at Talk:Number of the Beast, I can only assume that part of your education is missing for some reason.  Since an astronomer (Parajkoj) repeatedly say you know nothing about this subject, and noone called him out for saying that, I can only assume you don't know anything about this subject.  Having looked at the LBNL paper, I can tell that you're getting the contents backwards and missing parts, and reading your views into it instead of what the paper says.  You don't know anything about any subjects you have been talking about.  You haven't shown you know any way to research.  You are only making a mess and should just leave.  You have only shown that you are incapable of anything useful.  You are a prime example of the Dunning-Kruger effect.
If you want to prove me wrong, coherently state what you're trying to do for the articles you've been trying to work on.  That is, form a thesis statment, and bring in sources that directly support that statement.  This is stuff you have to know to graduate from high school, and you have demonstrated a complete inability to manage this.  Ian.thomson (talk) 17:06, 30 May 2011 (UTC)
replies: text: And again, you refuse to address any point.  I give up, you're a useless and bad editor, either because you're deliberately ignorant and uneducated and cannot realize this or because you're a troll.  Whatever the reason, this is the last time time I'll respond to you outside of warnings and reports. Ian.thomson (talk) 18:56, 30 May 2011 (UTC)
thread_title:  General response to Orphadeus 

message: In the introduction, it says extinction is measured in mag/kpc.  It is not clear whether extinction is A(bandpass), mentioned below and identified as "total extinction", and A's units are never unambiguously stated.  However, the units in the equation for N_H/A(V) imply that A has units of mags.  Does A have units of mag, or mag/kpc? Asterai (talk) 21:34, 1 July 2011 (UTC)
replies: text: A has units of magnitudes. I've removed the misleading statement in the lead, and mentioned the units when A (and N(H)) is introduced. Modest Genius talk 23:11, 1 July 2011 (UTC)
thread_title: Units?

message: If I might make a suggestion here: put up an example or two with clearly defined terms as to how reddening is calculated locally.  Pick a star say...300 parsecs out and walk the reader through the math step by step.  Actually seeing an example of the equation in action, with defined terms all the way around, would help a great deal here.  — Preceding unsigned comment added by 74.124.96.239 (talk) 00:25, 3 April 2013 (UTC)
replies: text: Agreed, that would be helpful. Please go ahead and add one. Modest Genius talk 12:13, 22 April 2013 (UTC)
thread_title: Example