Talk:Whirlpool Galaxy
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[edit] Image:M51 Whirpool Galaxy.JPG
An edit by anonymous user 219.76.96.9 lead me to http://antwrp.gsfc.nasa.gov/apod/ap020710.html, the original source of the image. The image is copyrighted, and as I assume that explicit permission has not been obtained to use it, I'm removing it from the page and flagging it as a copyvio. --Ardonik 02:00, Jul 29, 2004 (UTC)
- I've now obtained permission and re-instated the image. Arcturus 17:56, 10 Sep 2004 (UTC)
- Andromeda Galaxy also had an apparent copyvio image from http://antwrp.gsfc.nasa.gov/apod/ap040718.html. -- Curps 02:39, 29 Jul 2004 (UTC)
[edit] Incomplete/useless references
Some of the references on this web page are incomplete. "STSCI (2001)" simply cannot be used to check the validity of the information (a distance measurement). The Salo & Laurikainen reference is missing the volume number, which is needed for journal references. Someone should clean up these references. George J. Bendo 15:19, 20 September 2006 (UTC)
- Fixed. WilliamKF 18:59, 12 October 2006 (UTC)
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- Thank you WilliamKF. George J. Bendo 19:37, 12 October 2006 (UTC)
[edit] Comments on 15 October edts
On 15 October I removed a few rambling statements from the Whirlpool Galaxy article. Whoever had written this article would frequently discuss topics indirectly related or unrelated to M51. This includes a discussion on the large scale structure of the universe which was not appropriate here. I also removed a very poor, very misleading explanation of the interaction-induced spiral arm structure in M51. I may attempt to write a better description once I find a reference. (I may try either the Binney and Tremaine or Binney and Merrifield books for basic descriptions of the process. Papers by Toomre and Toomre may also contain good information.)
I have also revised the description of M51's group membership. Note that four references all indicate that NGC 5194 is not part of the M101 Group. The only places where such an assertion is made is the Ferrarese paper (which seems hesitant in drawing such a conclusion) and the Altas of the Universe website (which has not been reviewed for scientific accuracy like the journal articles cited in the M51 entry). If anyone disagrees with my conclusions, please indicate so here. George J. Bendo 00:43, 16 October 2006 (UTC)
[edit] Telescope size
You may want to use millimeters (mm) in describing telescope apeture. When converting from apeture in millimeters to apeture in inches, and vice versa, all you would need to do is multiply (in. to mm) or divide (mm to in.) by 25. The use of centimeters can throw one off, especially in the astronomy world, when telescopes under 4 inches are marketed in millimeters and etc. Rwboa22 20:48, 21 March 2007 (UTC)
[edit] Apperance of Whirlpool in a Telescope
I had the privledge to see the Whirlpool Galaxy (M51) on Tuesday night/Wednesday morning at a dark sky observing site north of Fort Indiantown Gap, Pennsylvania, using a 12-inch Dobsonian telescope. Although the comment in the article states that a 150 mm (6-inch.) telescope will show the spiral structure, that is only true with a refractor telescope, which does not have a central obstructuction (i.e. the secondary mirror). For best results, at least a 250 mm (10 in.) or higher telescope with a good wide-field eyepiece would be better. This dark sky sight, roughly 1,100 feet above sea level, allowed me to see a "hint" of spiral arm in the system, and works better at higher magnifications (100X and higher). Rwboa22 20:54, 21 March 2007 (UTC)
- While what you saw may be more accurate than the text, you cannot use your own personal observations to write Wikipedia articles. That would be original research, which is avoided in Wikipedia. Can you supply a reference to support your claim? (Alternatively, if the Wikipedia article is unreferenced, remove the information from the article.) Dr. Submillimeter 22:22, 21 March 2007 (UTC)
[edit] Dates of Sketch and telescope used: 1845 and/or 1847?
Just wondering: In this article the date below the whirlpool galaxy sketch (showing it to be a spiral) by Lord Rosse says 1845, and it is mentioned that he made the sketch with his 72-inch reflecting telescope, but the article on Lord Rosse says that the 72-inch telescope was not put into use until 1847. So, date-wise that seems rather strange: a sketch "attributed to" the 72-inch telescope seems to predate that telescope by two years.
Telescope date of use can be found at http://en.wikipedia.org/wiki/William_Parsons%2C_3rd_Earl_of_Rosse
Mnentro 13:31, 1 August 2007 (UTC)
