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Re: Lunars
From: Bill B
Date: 2005 Dec 10, 23:38 -0500
From: Bill B
Date: 2005 Dec 10, 23:38 -0500
> Bill, you wrote: > " I did not try changing temperatures but will do. I did occur > to me with Venus relatively low in the sky and high PB refraction could be > playing with me." > > By the way, I'm not suggesting that this will eliminate your errors (they're > insignificantly small anyway), but simply that it's interesting to see how > much a temperature change of a few degrees at low altitudes *might* change > the results of the clearing process. > > -FER Looks like I was pretty close to a rounding point. Using one shot with a -0.1 error, 2d F increase brought me from -0.1' to -0.2' error. It took a 10d F drop to go from -0.1' to -0.2' error. As the shots were done between 6:35 and 6:45 EST, and temp was 11d at 6:00 and dropping, I can be sure that it was at least that cold when I did the observations. Think it bottomed out at about 4d F. I was surprised that both an increase and decrease of temperature increased the bodies separation by 0.1' Simplistically, I would have thought that an increase in temperature (BP constant) would reduce refraction and lift the bodies less, hence a greater observed separation. A decrease in temperature would increase refraction, lifting the bodies more, and observed separation would be less. Back to the think tank on that subject. If I had a strong suit, refraction would not be it. I have no clue as to how pressure and temperature around St. Louis (maybe lower BP, higher temp?) might affect the outcome. Could it lift the lower body (Venus) less than predicted by local conditions, increasing the apparent separation as calculated from local conditions? No idea. Bill