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I witnessed the new moon rise just ahead of a sunrise at the very same spot on the horizon. How often could I plan on looking for that occurrence again?

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    $\begingroup$ What date did you see this? Where in the world are you located?? And when you say "the same" spot, how accurately is it the same? If there were trees on either side of the rising point, both objects would have risen between the trees? $\endgroup$
    – JohnHoltz
    Commented Nov 20, 2022 at 15:04
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    $\begingroup$ It's eclipse season, so the Moon is close to the ecliptic at New & Full Moon. Also see eclipsewise.com/oh/ec2022.html $\endgroup$
    – PM 2Ring
    Commented Nov 20, 2022 at 15:39
  • $\begingroup$ Hmm not sure about this observation. From where I am (London) the moon rose at about 3 AM, almost due East (95 degrees). The sun rose nearly five hours later at 7:45 and South East (125 degrees). Where are you located? $\endgroup$
    – James K
    Commented Nov 20, 2022 at 17:45
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    $\begingroup$ It's not going to be New Moon until a few days from now, so it must have been a nearly a month ago, at least. $\endgroup$
    – notovny
    Commented Nov 20, 2022 at 18:13
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    $\begingroup$ That's true, so I think this is unclear. I'm not convinced that the existing answer is relevant. (I don't think the OP is using new moon to mean "the moment when the moon's ecliptic longitude is equal to that of the sun, but to mean "when the crescent is first visible) So I vote to close this as needing the details where and when $\endgroup$
    – James K
    Commented Nov 21, 2022 at 21:28

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At exact new moon, moon and sun can be separated by at most 5 degrees, as the lunar orbit around earth is tilted a bit (5 degrees) against the earth's orbit around the sun (what we call the ecliptic).

As any pair of two planes has one line in common, there are situations where both the sun-earth connecting line and the earth-moon line nearly coincide, and that's either a solar eclipse (at new moon) or a lunar eclipse (at full moon). Most of the time, new moon and full moon happen in directions where the planes are distant enough so that the shadows miss earth or moon, and that's why eclipses don't happen every 2 weeks.

But if a solar eclipse happens at your place around sunrise, moon and sun will rise at exactly the same point, with the moon covering the sun.

So, a same-point rise happens perfectly at solar eclipses, and if you want the (nearly) new moon to rise at the same place, only shortly before the sun, go some hours or a day backwards from a solar eclipse. Depending on the accepted difference in direction, a near-eclipse will do as well (meaning a situation where the moon's shadow comes close to earth).

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