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lunar azimuth cycle

6 replies [Last post]
Joined: 2012-01-25

For a naked-eye observer who watches the moon-rises the rise position changes over the course of a "month". If we start at the most northly position, the rise on successive days moves farther south on the eastern horizon until the most extreme southern position for that "month" is reached. Then the rises occur a bit farther to the north each day until we are back at the extreme northern position again.

My question: What is the length of this version of a lunar "month"?

Joined: 2012-01-25
More Lunar Azimuth Cycle

I graphed data for the azimuth of moon rises using data from the Griffith Observatory (
The period of my graph is about 27.5 days. This is not a match for any of the lunar "months" identified on Wikki. Can anyone help?

Steven Logan
Sidereal Month

I believe what you are observing is related to the moon's movement relative to the background stars which repeats in a time period called a sidereal month. A sidereal month encompasses 27.3 days. Check out
and search articles on the sidereal month.

David T. Szumski
29 28 days usually righht ?

I make Astronomical calculation posters never knew this about the azimuth cycle

Penny Aparicio

I need to know, what is the highest degrees above the horizon the moon ever gets during the year in the Yakima Valley ? can you please help me figure out this please?

David T. Szumski
Yakima Valley

Give me the location state coordinates if possible I will give you precise calculations

David T. Szumski
e mail me at I will give the height descending and ascending using Excel using MICA DATA it is very precise

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