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:::::::I read the beginning of [http://adsabs.harvard.edu/abs/1973PASP...85..579T] with great interest. Unfortunately, though it says, "The dynamical methods all depend on the fact that we can measure both proper motions, in arc seconds year<sup>-1</sup>, and radial velocities, in km sec<sup>-1</sup>," it doesn't go into detail on how we can do that. The arc seconds/year, of course, can just be observed - but how do we measure the radial velocities? (I think your answer would make a great addition to some astronomy article!) --[[User:EvanW|EvanW]] 14:51, 20 January 2010 (EST)
:::::::I read the beginning of [http://adsabs.harvard.edu/abs/1973PASP...85..579T] with great interest. Unfortunately, though it says, "The dynamical methods all depend on the fact that we can measure both proper motions, in arc seconds year<sup>-1</sup>, and radial velocities, in km sec<sup>-1</sup>," it doesn't go into detail on how we can do that. The arc seconds/year, of course, can just be observed - but how do we measure the radial velocities? (I think your answer would make a great addition to some astronomy article!) --[[User:EvanW|EvanW]] 14:51, 20 January 2010 (EST)
(Unindented reply) Hello EvanW, I went and checked and we do not have a radial velocity page on this site. I will definitely have to put creating that page on my "to do" list since it is an important concept in astronomy. To answer your question though, in short, radial velocity speed at which an object is moving away from or toward an observer along the line of sight. We calculate this by observing displacement of spectral lines from their normal position in the observed object's spectra. Blueshifted if the object is moving towards s, redshifted if its moving away. The larger the blueshift or redshift, the larger the radial velocity. I hope that helps. --[[User:BMcP|BMcP]] 15:17, 20 January 2010 (EST)
== images uploaded ==
== images uploaded ==
[[Conservapedia:Image upload requests#Astronomy Images|your images, sir]] [[User:JacobB|JacobB]] 17:56, 9 January 2010 (EST)
[[Conservapedia:Image upload requests#Astronomy Images|your images, sir]] [[User:JacobB|JacobB]] 17:56, 9 January 2010 (EST)