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Re: Grenadine Lunar Distances
From: Fred Hebard
Date: 2003 Feb 4, 17:53 -0500
From: Fred Hebard
Date: 2003 Feb 4, 17:53 -0500
This is my second attempt to post Arthur's message. I hope Herbert will care to respond to Arthur; I would if I were capable. But I will take this opportunity to ask a question. I have been computing the comparing distance between the moon and an object (the one _not_ corrected for parallax and refraction), and that has been varying. For instance, the moon and Jupiter were separating at 35.3' per hour between 2:00 and 3:00 GMT on 12/27/02 while the sun and moon were separating at 27.0' per hour between 20:00 and 21:00 GMT on 1/11/03. Not all this can be attributed to the hourly movement of the sun; is all the rest from their not moving in the same direction or are there additional factors? Fred >Herbert, Fred, >Here is the second email that wouldn't post to the list. >Arthur >=============== > >Herbert, > >Once again, confusion leads to greater understanding. I had not >considered this disaggregated view of the moon's motion relative to the >sun. Am I correct in thinking of the change in distance as a vector >resulting from difference between the vectors of their individual motion >against the celestial sphere? I hope I am not opening a can of worms >here. I had been focused on the single dimension of the moon pulling >away from or closing with the moon, which for practical purposes is >fine, but I am interested in understanding the components. Thanks. > >Arthur > > >----Original Message Follows---- >From: Herbert Prinz>Reply-To: Navigation Mailing List >To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM >Subject: Re: Grenadine Lunar Distances >Date: Mon, 3 Feb 2003 15:25:40 +0000 > >Arthur, > >Oops, I confused two output parameters from my program. The value of 24' >/ h >which I have quoted is the topocentric apparent motion of the moon >w.r.t. >the celestial sphere, i.e corrected for parallax and refraction. It is >irrelevant in this context. The change in distance to the sun is indeed >21'. >The two values differ in two respects: 1. The moon is not moving exactly >into the direction of the sun. 2. The sun itself moves east at a speed >of >2.5' / h. Sorry for the confusion. > >Herbert Prinz > > > >Arthur Pearson wrote: > > > * Regarding hourly rate of change in distance: for the Jan. 10 lunar >I > > got 21', Herbert 24', Fred 27'. I still get 21'/hour, but this is for > > the apparent distance after correction for parallax and refraction. >For > > the geocentric distance, I get an hourly change of 28' for the Jan. 7 > > lunar, 27' for the Jan. 10 lunar. This seems to explain the >difference > > with Fred, still not sure with Herbert. > > >Arthur Pearson >arthurpearson@hotmail.com > > >Arthur Pearson >arthurpearson@hotmail.com > >_________________________________________________________________ >Tired of spam? Get advanced junk mail protection with MSN 8. >http://join.msn.com/?page=features/junkmail -- -------------------------------------------------------------------------- Frederick V. Hebard, PhD Email: mailto:Fred@acf.org Staff Pathologist, Meadowview Research Farms Web: http://www.acf.org American Chestnut Foundation Phone: (276) 944-4631 14005 Glenbrook Ave. Fax: (276) 944-0934 Meadowview, VA 24361