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Re: Real accuracy of the method of lunar distances
From: Jared Sherman
Date: 2004 Jan 14, 14:02 -0500
From: Jared Sherman
Date: 2004 Jan 14, 14:02 -0500
[Geo. Huxtable] Ah, a crux. I'm afraid even I may be understanding this thanks to all the patient re-explanations. For the sake of simplicity, I think we can for a moment ignore the question of whether/when the moon appears to move more rapidly against the stars, and stick to the crux of things. Perhaps we could perform a simple exercise here: Assume that I take a lunar distance measurement at 5:30AM. And then again at midnight. 1-How long does it take me to take the lunar, i.e. to measure the distance from the moon to the other body? Is that "instantaneous" observation affected by the speed of the moon's motion? 2-Am I doing anything else, which is not "instantaneous", which will be affected by the "speed" of the moon? 3-Bottom line time. Perform the above observations and timings, assuming both the fastest and slowest "speed" of the moon for the readings when the moon is overhead, and on the horizon. Clear the lunars from both times. (Or all three, to use both horizons.) Are the results ANY different, allowing for a different speed of the moon? And if #3 seems unclear, that's because I'm not familiar with the mechanics of clearing a lunar, so please feel free to re-structure the experiment allowing for the realities of the process. Theories are fine, but what are the actual numbers? How does the presumed change in lunar "speed" affect readings, if it does at all? To what amount of time? Five seconds? One? Just what IS the magnitude of error that we are chasing here?