~~The "Orientation of Celestial Pole" is equivalent to the angle of the
> Earth's Axis of Rotation relative to the Galactic Equator. You can see from
> the following dialog that even experts make mistakes (not just me). Also my realization
> that this calculation would require a working understanding of "Celestial
> Trigonometry" ~~ My editorial comments are presented in [square brackets] in the forum notes below. MP. ~~ > >
> >
>
http://cs.astronomy.com/asy/general_discussion/f/27/t/31176.aspx?sort=ASC&pi2390\
31358=3
> >
> >
> > Posted by jim_slater
> > on Sat, Jul 7 2012 8:59 AM
> >
> > Except that the Solar System leaning back, not forward, at 60 degrees as
> it orbits counter-clockwise around the center of the Milky Way.
> >
> > Centaur
> > Posted by Centaur
> > on Sat, Jul 7 2012 4:58 PM
> >
> > jim_slater
> >
> > Except that the Solar System leaning back, not forward, at 60 degrees as
> is orbits counter-clockwise around the center of the Milky Way.
> >
> > As described more fully two years ago in my third post within this
> thread.
> >
> > For astronomical graphics, including monthly wallpaper calendar, visit:
> >
> > www.CurtRenz.com/astronomical
> >
> >
> > jim_slater
> > Posted by jim_slater
> > on Sat, Jul 7 2012 9:43 PM
> >
> > Thanks Centaur, at least that means I've got the right picture. You also
> mention that the "celestial north pole lies about 27° away from the galactic
> equator". I'm beginning to grasp this. I used to think that it was simply a
> matter of the sum or difference between the inclination of the ecliptic
> relative to the galactic plane (~60 degrees) and the tilt of the earth's
> rotational axis (~23.5 degrees) relative to the ecliptic. Apparently not. Could you explain how this
> 27 degree value can be calculated?
> >
> > jim_slater
> > Posted by jim_slater
> > on Sat, Jul 7 2012 9:51 PM
> >
> > Yes, this illustration is very misleading. I took a bunch of estimates
> of the solar system's distance north of the galactic equator and came up
> with about 64 light years. Most estimates put us at about 26,000 light
> years from the galactic center. This means that we only subtend and angle
> of about 0.14 degrees from the galactic center, which is less than the
> orbital inclination of most planets in the solar system! The illustrations
> I've seen that depict the earth's sinusoidal path around the galaxy greatly
> exaggerate this angle.
> >
> > Centaur
> > Posted by Centaur
> > on Sat, Jul 7 2012 10:11 PM
> >
> > jim_slater
> >
> > Thanks Centaur, at least that means I've got the right picture. You also
> mention that the "celestial north pole lies about 27° away from the galactic
> equator." I'm beginning to grasp this. I used to this that it was simply a
> matter of the sum or difference between the inclination of the ecliptic
> relative to the galactic plane (~60 degrees) and the tilt of the earth's
> rotational axis (~23.5 degrees). Apparently not. Could you explain how this
> 27 degree value can be calculated?
> >
> > You're welcome, Jim. Actually I essentially wrote that the North
> Galactic Pole lies about 27° from the Celestial Equator [wrong - correction to follow - MP]. However, it
> logically follows that what you claimed I wrote is also true.
> >
> > The ecliptic and celestial equator intersect at the equinox points. If
> the galactic equator intersected the others at the equinox points, your
> simplified calculation would be correct. However, the galactic equator
> intersects the ecliptic near the solstice points. Hence the need for
> spherical trigonometry to solve your problem:
> http://en.wikipedia.org/wiki/Spherical_trigonometry
> >
> > For astronomical graphics, including monthly wallpaper calendar, visit:
> >
> > www.CurtRenz.com/astronomical
> >
> >
> > chipdatajeffB
> > Posted by chipdatajeffB
> > on Sat, Jul 7 2012 10:13 PM
> >
> > Just fyi, there is a freeware program called "Where is M13"" that might
> interest you. It shows the location of all the Messier objects relative to
> our location and the location of the center of the Milky Way. I find it
> helpful when explaining the size and shape of the Milky Way during outreach
> events.
> >
> > One thing that's interesting to do with it is "turn on" all of the
> Messier globular clusters and see how they're distributed around the galaxy.
> >
> > The universe is not only stranger than we imagine, it's stranger than we
> CAN imagine. --- JBS Haldane
> >
> > Come visit me at Comanche Springs Astronomy Campus (we're on Google
> Maps) in Texas.
> >
> > www.3rf.org
> >
> > jim_slater
> > Posted by jim_slater
> > on Sun, Jul 8 2012 8:40 PM
> >
> > I don't mean to be nit-picky Centaur, but you did say, "The Celestial
> North Pole lies about 27° away from the Galactic Equator" on Wed, Mar 9
> 2011 8:56 PM [which was correct].
> >
> > Centaur
> > Posted by Centaur
> > on Sun, Jul 8 2012 9:51 PM
> >
> > jim_slater
> >
> > I don't mean to be nit-picky Centaur, but you did say, "The celestial
> north pole lies about 27° away from the galactic equator" on Wed, Mar 9
> 2011 8:56 PM [as opposed to his incorrect statement that "the North
> Galactic Pole lies about 27° from the celestial equator" as stated by Centaur on Sat, Jul 7 2012 10:11 PM [see commentary above]
> >
> >Centaur: I stand corrected. Thank you, Jim. In my second post of 2012 JUL 07 I
> was referring to my comment of 2010 JUL 04 which was referenced in my first
> post of 2012 JUL 07. I did not realize I had made another post in 2011 MAR
> 09, which you found. Nevertheless, as noted in my second post of 2012 JUL
> 07, both comments are correct. Sorry, but such misunderstandings arise when
> people resurrect four-year-old threads for which memories of posters have
> faded, especially for senior citizens like me. In any event, Jim, welcome
> to the discussion board.
> >
> > For astronomical graphics, including monthly wallpaper calendar, visit:
> >
> > www.CurtRenz.com/astronomical
> >
> >
> > jim_slater
> > Posted by jim_slater
> > on Mon, Jul 9 2012 8:06 AM
> >
> > Thanks Centaur. So, just for the sake of disambiguation, the Celestial
> North Pole is oriented at 27 degrees above the Galactic Equator? I picture
> this in my mind as being kind of like Uranus 'rolling' along the ecliptic
> [although at and angle of only 8 degrees away from the ecliptic plane].
> >
> > Centaur
> > Posted by Centaur
> > on Mon, Jul 9 2012 4:10 PM
> >
> > jim_slater said,
> >
> > ...the Celestial North Pole is oriented at 27 degrees above the Galactic
> Equator?
> >
> > Centaur: Yes, as a point on the galactic equator in Cassiopeia lies closest to
> the north celestial pole at a distance of 27°. Or perhaps we might say 27°
> below, since the rotation of the Earth could be considered retrograde to
> that of the stars revolving around the galactic center.
> >
> > For astronomical graphics, including monthly wallpaper calendar, visit:
> >
> > www.CurtRenz.com/astronomical
> >
> >
> > jim_slater
> > Posted by jim_slater
> > on Tue, Jul 10 2012 3:24 AM
> >
> > Thank you Centaur. Finally, after ten years of trying to get my head
> around this, something finally went 'click'. I get it!
> >
> > Here's another interesting page of Celestial Trigonometry:
> answers.yahoo.com/.../index
> >
> > I'm still tinkering with Excel to get this to work. There's always the
> next missing piece...
> >
> > jim_slater
> > Posted by jim_slater
> > on Tue, Jul 10 2012 9:15 PM [me still needing more clarification]:
> >
> > Centaur, here we go again... "Cassiopeia lies closest to the north
> celestial pole at a distance of 27°"
> >
> > I thought the North Celestial Pole would be located in Ursa Minor,
> centering almost on Polaris. I'm not sure how Cassiopeia fits into this
> picture.
> >
> > Centaur
> > Posted by Centaur
> > on Tue, Jul 10 2012 10:17 PM
> >
> > jim_slater
> >
> > Centaur, here we go again... "Cassiopeia lies closest to the north> celestial pole at a distance of 27°"> >> > I thought the North Celestial Pole would be located in Ursa Minor,> centering almost on Polaris. I'm not sure how Cassiopeia fits into this> picture.> >> > Centaur: If you were to quote my full sentence, the mystery may be resolved:> "Yes, as a point on the Galactic Equator in Cassiopeia lies closest to the North Celestial Pole at a distance of 27°." That was in answer to your question which I quoted initially "...the celestial north pole is oriented at 27 degrees above the galactic equator?" Naturally, an infinite number of points not on the galactic equator are closer than 27° from the NCP.> >> > Indeed, the North Celestial Pole is currently in Ursa Minor and is less than 1° from Polaris. The point on the Galactic Equator that lies closest to to the North Celestial Pole is within Cassiopeia. [Aha! Moment! - MP] Centaur: I suggest reading a star map that includes the Milky Way. You will see that where the Milky Way appears closest to the NCP and Polaris, it lies within Cassiopeia.> >> > For astronomical graphics, including monthly wallpaper calendar, visit:> >> > www.CurtRenz.com/astronomical> >>