8 replies to this topic

[Lightbucket12]

“With the culmination of the 18.6-year cycle of the Moon 2006 and again in 2024-2025, also called the Major Lunar Standstill, we are afforded the unique opportunity to observe the monthly, annual, and 18.6 year wandering of the Moon.  The 18.6-year cycle is caused by the precession of the plane of the lunar orbit, while this orbit maintains a 5 degree tilt relative to the ecliptic.  At the peak of this cycle, the Moon’s declination swings from -28.8 degrees to +28.8 degrees each month.  What this means is that each month for the years 2005-2007 and also 2023-2026, the Moon can be seen rising and setting more northerly and also more southerly than the solar extremes, and will transit monthly with altitudes which are higher in the sky than summer Sun and lower in the sky than the winter Sun.”

 

Is anyone observing, monitoring or measuring/documenting this phenomenon.  If so how are you measuring or documenting the cycle peak?

 

Bert

[John_Moore]

Hi Bert

 

This is a fascinating area of lunar orbital mechanics, which, as seen in the two graphics below, can get quite complicated to explain in non-easy terms. However, that said, perhaps they might give an idea as to what is happening from the tilts point of view, involved with both the Moon and Earth. 

 

The first graphic is for the Major Standstill in 2025, while the second graphic is for the Minor Standstill in 2034.

 

John

 

Graphics: Copyright John Moore

 

 

Edited by John_Moore, 14 April 2024 - 09:25 AM.

[Lightbucket12]

Hi Bert

 

This is a fascinating area of lunar orbital mechanics, which, as seen in the two graphics below, can get quite complicated to explain in non-easy terms. However, that said, perhaps they might give an idea as to what is happening from the tilts point of view, involved with both the Moon and Earth. 

 

The first graphic is for the Major Standstill in 2025, while the second graphic is for the Minor Standstill in 2034.

 

John

 

Images: Copyrighted to John Moore

 

 Thank You John

 

The graphics are amazing and are very helpful as they show the edge on relationship which, for me, is not intuitive and difficult to but into perspective and decode.  However the dimensional representation with the addition of the Moon’s tilt plane/orbital box, nodes and Sun are extremely helpful in understanding the relationships of the individual parts that make up the whole.  Nicely done.

 

I first became aware of the Lunar Standsill phenomenon while studying Luna Cognita’s section on The Earth-Moon Systems as it relates to Changing Declinations and Lunar Standsill, both major and minor, so I had familiarity with the component parts but was unable to see the larger picture, forest through the trees.  I also looked at other sources but still suffered from mental myopia.

 

What can I say, a picture (in this case two) is worth a thousand words.

 

Thanks again,

 

Bert

[John_Moore]

Hi again, Bert.

 

I can see how the graphics are a bit hard to interpret, as I could have explained them more (I have accompanying text prepared already, but this would be for the book).

 

I found that in discussing Standstills (in CN and other forums) in the past, that it can get very long-winded, confusing etc.,, leading to further explanations required, but when one gets a grasp on what is actually happening, it all becomes clear in the end (doh  ).

 

The nodes (graphic 3 -- where the orbital movement of the Moon crosses the Ecliptic Plain of the Sun where all the other planets revolve around in, too) are what causes the confusion mainly, I think, in that over the period of the 18.6-year cycle, they rotate, and so trying to get one's head around that was, for me anyway, a defining factor as to why Standstills occur.

 

I'm including two other graphics to compliment the already-mentioned 2025 Major Standstill and the 2034 Minor Standstill just to confuse you and viewers even more  I'll know you'll forgive me.

 

John

 

Graphics: Copyright John Moore

 

 

 

[Lightbucket12]

Hi again, Bert.

 

I can see how the graphics are a bit hard to interpret, as I could have explained them more (I have accompanying text prepared already, but this would be for the book).

 

I found that in discussing Standstills (in CN and other forums) in the past, that it can get very long-winded, confusing etc.,, leading to further explanations required, but when one gets a grasp on what is actually happening, it all becomes clear in the end (doh  ).

 

The nodes (graphic 3 -- where the orbital movement of the Moon crosses the Ecliptic Plain of the Sun where all the other planets revolve around in, too) are what causes the confusion mainly, I think, in that over the period of the 18.6-year cycle, they rotate, and so trying to get one's head around that was, for me anyway, a defining factor as to why Standstills occur.

 

I'm including two other graphics to compliment the already-mentioned 2025 Major Standstill and the 2034 Minor Standstill just to confuse you and viewers even more  I'll know you'll forgive me.

 

John

 

Graphics: Copyright John Moore

 

Thanks John,

 

Yes confusion reigned supreme but I think I have it sorted out… some what…with many reviews of your material and re-reads of pertinent sections in Luna Cognita.

 

PERTINENT INFORMATION

 

*. Equinox occurs when the Earth’s orbital plane crosses the Ecliptic plane, Vernal Equinox on the ascending node, Autumnal Equinox on the descending node.

 

*. Moon’s orbit will spend half orbit north of the Ecliptic, other half south of the Ecliptic.

 

*. Nodes are the two points where the Moon crosses the Ecliptic.  Ascending node equals the point where the Moon passes from south to north.  Descending node from north to south of the Ecliptic.

 

*. Nodes slowly rotate westerly along the Ecliptic in a retrograde motion to the Moon’s eastward motion (“the regression of the nodes”) taking 18.6 years for one revolution resulting in Major Standstill with a Minor Standstill at the midpoint, year 9.

 

*. Major Lunar Standsill occurs (is viewed) along the horizon when the Moon’s rising and setting points reach there maximum declination north or south of the Sun each winter and summer solstice.

 

Noted, the above points are direct quotes or paraphrased from Luna Cognita, Volume 1, Earth-Moon System 2-8 - 2-11 and other sources.

 

THE MECHANICS

 

Major Moon Standstill occurs 7 March ‘25 through 22 March ‘25 with the Vernal Equinox on 20 March ‘25.

 

Moon’s tilt relative to the Ecliptic is 5.2 degrees.  Earth’s tilt relative to the  Ecliptic is +23.4 degrees North.

 

7 March ‘25, pre Vernal Equinox, the Moon is on the ascending node 5.2 degrees above the Ecliptical Plane.  The Earth’s tilt along the Equatorial Plane relative to the Ecliptic is +23.4 degrees (North) hence the total degree change, as viewed along the horizon is +28.6 degrees North.

 

Post Vernal Equinox, 22 March ‘25 ( 15 days or one half lunation since 7 March ‘25) the Moon is on the descending node 5.2 degrees below the Ecliptic, the Ecliptic is -23.4 degrees South of the Earth’s Equatorial Plane resulting in a -28.6 South orientation along the horizon.

 

Sooo!!  I think that’s how it works.

 

”what say you”

 

Bert

Edited by Lightbucket12, 24 April 2024 - 07:59 PM.

[John_Moore]

Thanks, Bert.

 

I don't have the books of Cognita, but looks like the author (and you) have it right.

 

In orbital mechanics, for example, like the Earth, Moon and Sun orbiting around each other, it's called a 'Complex Orbit', and so can get quite confusing (link to the 'Three-body Problem' -- not the Movie  ).

 

John

Edited by John_Moore, 26 April 2024 - 03:37 PM.

[groom]

This might be an oversimplification, but I was trying to observe/photograph the Moon recently in the days before and after last quarter just before dawn, which would put the Moon near its meridian crossing. I noticed that the Moon was positioned much lower in the sky than usual. This last month we had a solar eclipse only two weeks after the Spring Equinox, and the path of totality went from south to north, which put the ascending node at new moon. The moon at last quarter is positioned 90 degrees away so since the eclipse was at ascending node, the moon last month and this month had to have been at or close to its southern nadir at last quarter and conversely at or near a maximum north of the ecliptic at first quarter, close to the zenith at meridian crossing.

[Krukarius]

https://astro-geo-gi...h-fluctuations/

The major lunar standstill is a perfect occasion for chasing distant landscape features behind which the Moon will rise or set at extremal azimuths.

[John_Moore]

https://astro-geo-gi...h-fluctuations/

The major lunar standstill is a perfect occasion for chasing distant landscape features behind which the Moon will rise or set at extremal azimuths.

Many thanks for the link, and full access to the paper, which looks very interesting from the outset.

 

John