With the known latitude coordinate of the observing position, how to find the altitude of the moon when it is high, i.e when it crosses the local meridian?

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    $\begingroup$ May be this is out of your scope, but I saw those programs may help you. There is a cool software Digital planetarium application, free to download. And another one here but shareware Starry Night $\endgroup$ – Ahmed Hamdy Dec 17 '13 at 9:11
  • $\begingroup$ Thanks :) But, I'm looking for a mathematical approach as it was asked in one of my astronomy homeworks. $\endgroup$ – Ken Dec 17 '13 at 17:48
  • $\begingroup$ If it is homework, shouldn't you be attempting to research the answer yourself, or figure it out for yourself? The point being to help you comprehend what is going on, not just obtain an answer? $\endgroup$ – Jeremy Feb 18 '14 at 4:04
  • $\begingroup$ @Jeremy That is exactly what I did (sort of) :) AstroFloyd's answer did help me to comprehend the concept a bit, and later I got a clarified answer from my class. $\endgroup$ – Ken Feb 18 '14 at 13:12

The transit altitude of an object does not only depend on your latitude ($b$), but also on the declination of the object ($\delta$): $$h_\mathrm{tr} = \arcsin\left(\sin b \sin \delta + \cos b \cos\delta\right).$$


With a lot of difficulty if you want to do it numerically by yourself. The Moon's orbit is very complex.

Far and away the easiest method would be to use NASA's HORIZONS service for calculating ephemerides, which will get you very comprehensive and accurate information on objects at your specified times.

I don't think that HORIZONS can directly return the time that the Moon is at its maximum altitude. However, if you can write some basic computer code then it shouldn't be difficult to query the ephemerides with a precise (say 1 minute) time interval and find the maximum altitude from there.

  • $\begingroup$ Thanks :) But, I'm looking for a mathematical approach as it was asked in one of my astronomy homeworks. $\endgroup$ – Ken Dec 17 '13 at 17:58
  • $\begingroup$ Can you please give references to explanations of the moon orbit, especially as it looks from earth? I'm puzzled that the moon and the sun have interchangable paths on the sky between winter and summer. Is it possible to easily explain this? Would this be a good question (on its own) to ask in astronomy.stackexchange.com? Many thanks! $\endgroup$ – George Aug 11 '16 at 13:11

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