Robert Matson wrote: > On the subject of orbital precession (i.e. nodal regression) you asked: > > > So, what would account for such a huge precession of the plane of orbit? > > The earth's equatorial bulge. Yeah, I just realized that a minute ago. Just as a charged sphere "looks like" a point charge at its center from outside the sphere, a spherical object "looks like" a point mass at the center only when its density depends solely upon the distance from the center. Because of the earth's rotation, it more nearly resembles such a sphere, but with a huge mountain range encircling the equator. As the ISS approaches the equator from the north, it's deflected downloads (toward the south); as it's pulling away from the equator, it's deflected upwards (it's once again deflected as it crosses the equator from south to north). The situation is similar to a ray of light being slightly shifted in position as it passes at an angle through a plate of glass. So, as you note, all satellites (except those in an equatorial or polar orbit) would be affected; the degree would depend upon their altitude (so Hubble, in a higher orbit, would be less deflected). ----------------------------------------------------------------- To unsubscribe from SeeSat-L, send a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@satobs.org List archived at http://www.satobs.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Thu Dec 04 2003 - 14:56:14 EST