Talk:Celestial sphere

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Image[edit]

A Wikipedian out there who is good with 3D modeling could make a very slick image for this page. I know there is already an image but it would be pretty easy to make it a lot nicer. -Craig Pemberton (talk) 02:37, 22 September 2009 (UTC)

Check out Commons. --Traveler100 (talk) 17:30, 22 September 2009 (UTC)

Contradictory statement[edit]

Hi,

The statement that the sun rotates 1 degree to the east every day resulting in 4 "extra" minutes being required in the diurnal motion for the sun to reappear at the same meridian appears to be contradictory.

If the earth rotates from west to east and the sun moves east over its ecliptic, then the sun should appear 4 minutes earlier at the same point. This is substantiated by the rest of the numbers in the article.

Someone please let me know if I am not understanding...or if I am right, please edit and correct. I do not feel qualified to do so.

Thanks Madan

-- I believe you're not understanding. The article is correct. The sun is moving eastward; the earth is rotating west to east. The earth takes 23h56m04s to return to the same orientation with respect to the fixed stars; meanwhile, the sun has drifted eastward a bit more. So, the earth has to keep rotating for another 3m56s before it comes into the same orientation with respect to the sun. Put another way, successive meridian transits of a star occur on a 23h56m04s cycle (1 sidereal day), while successive meridian tranits of the sun take a little longer (1 solar day). -- JThorstensen

some questions?[edit]

hi, i am only an beginner in astronomy. i am quite confused about the concept of celestial sphere. First, does the sphere means the whole universe(it contains the constellations)?or are the constellations inside the galaxy? second , do all stars complete its rotation in 23h56mins(even the giants,sun,etc)? third, can we gaze the stars on the southern celestial sphere if we're on the northern sphere on earth? last, is the radius of the celestial sphere equal to the distance of earth to sun? thanks-Mayer

who invented the celestial sphere?[edit]

who invented the celestial sphere? who invented the celestial sphere? who invented the celestial sphere? —The preceding unsigned comment was added by 124.181.125.145 (talk) 08:39:22, August 19, 2007 (UTC)

Northern Pole Star[edit]

So will our northern reference pole star change to another star in the future Risingsun56 (talk) 16:22, 24 October 2008 (UTC)

Yes (see Polaris). --Roentgenium111 (talk) 20:18, 13 June 2009 (UTC)
And so will we change the celestial coordinates?Friendly Person (talk) 18:21, 1 October 2011 (UTC)

Eudoxan planetary model[edit]

As this article presently stands, the 2nd paragraph on the Eudoxan planetary model seems only very thinly related to the subject of the article. Why is it there? Friendly Person (talk) 22:21, 9 October 2011 (UTC)