We also simply call it "prime vertical crossing." -- Richard Langley
Quoting "Roger W. Sinnott" <[email protected]>: > Hi Greg, > > The east-west equivalent of the meridian is called the prime vertical. W. > Chauvenet's Manual of Spherical and Practical Astronomy (1863) notes that it > is very useful for determining an observer's latitude. > > The method involves setting up a transit instrument in the prime vertical, > then timing when a star crosses it in the east and later in the west. > Chauvenet speaks of a star's "transits over the vertical circle." > > -- Roger > > > ----- Original Message ----- > From: "Greg Gómez" <[email protected]> > To: <[email protected]> > Sent: Wednesday, January 14, 2009 12:29 PM > Subject: East/West "meridian?" > > > > > > Hello: > > > > The last full moon I was taking a walk and was marveling that when the > > moon is near it's northern extreme, it is quite high when it crosses 90 > > degrees azimuth. > > > > A question occurred to me: > > Is there an east/west equivalent to the meridian? In other words, what > > is the term for the great circle that goes through azimuth 90 and 180 > > degrees and through the zenith? > > > > Also, is there a term for when an object crosses that line? > > > > Thanks! > > Greg > > > > > > > > > > > > --------------------------------------------------- > > https://lists.uni-koeln.de/mailman/listinfo/sundial > > > > > > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > > =============================================================================== Richard B. Langley E-mail: [email protected] Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics Engineering Phone: +1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ =============================================================================== --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
