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Some things explained which happen between heaven and earth

Solstices (solar standstills)

On winter solstice (around December 21st) the Sun is lowest in the southern sky and this causes the shortest day-time. On summer solstice (around June 21st) the Sun is highest in the more northern sky and thus the longest day-time. This is repeated every year (the tropical year).
Solstices
The paths of the solstices. Looking down on Calanais I (using Stellarium)

Lunar standstills

The Moon has something similar, but its path oscillates around the Sun’s path. The Moon’s peak position is repeated every 18.6 year (the lunar nodal cycle). The peaked Moon outside the possible Sun’s paths is a major lunar standstill, while the peaked Moon inside the possible Sun’s paths is a minor lunar standstill. For the near skyline observations at Calanais I: The southern major lunar standstill will be most interesting as the Moon is lowest in the sky.
Solstices
The paths of the solstices and lunar standstills. Looking down on Calanais I (using Stellarium)

Where and when are the standstills

With the naked eye, a (near) solstice event can be witnessed every day over a period of around four weeks. A (near) lunar standstill event can be witnessed every 27.3 days (the tropical month) over a period of some 18 months. See for a general idea of dates the below figure. This can of course only be witnessed when it is not close to New Moon and if there are no clouds, and that happens on average during less than 10% of the events.
Dates and altitudes of standstills
Height (apparent altitude) of the solstices and lunar standstills in the sky (using ARCHAECOSMO package)

The Sleeping Beauty and the Moon

The possible reason why Calanais I site was built at its very location, is that the Moon’s southern major standstill events almost touch the skyline. This skyline is made up of hills of The Sleeping Beauty range. The Sleeping Beauty range could have a mythological meaning in former (and present) times.
Moon over Sleeping Beauty (G. Ponting)
The Moon emerges from and skims over The Sleeping Beauty range (photo © G. Ponting, 2006)
<permission gotten from Gerald Ponting to use on my web site, 2023>

When to observe the Moon from Calanais I

Top 11 lowest

Date of (near)

southern major standstill

Lunar
phase

1

22/03/2025

🌖

2

09/10/2024

🌒

3

01/09/2025

🌓

4

15/08/2024

🌔

5

05/11/2024

🌒

6

01/04/2024

🌖

7

11/09/2024

🌓

8

23/02/2025

🌔

9

26/01/2025

🌔

10

05/03/2024

🌘

11

18/04/2025

🌖

12

30/02/2024

🌒

As the Moon moves quite fast through its path, the moment of a lunar standstill is depending on the site’s latitude and longitude. But it is also depending if the Moon is at its rise, transit or set position. For Calanais I, at the Moon's transit position; the southern major standstill happens on 2025, March 22nd.
As said earlier: Near major southern lunar standstills can be witnessed every 27.3 days within some 9 months before and after this date. Here are the dates and phases of the top 11 (near) southern major standstill events that are lowest in the sky seen at Calanais I (using ARCHAEOCOSMO package).

Moon on March 22, 2025
Moon seen in Calanais I during the southern major standstill event on 22 March 2025 (using Stellarium)

For more information

QR code lunarstandstills
Some things explained which happen between heaven and earth by Victor Reijs is licensed under CC BY-NC-SA 4.0

Acknowledgements

I would like to thank people, such as Gerald Ponting, Emma Rennie, Georg Zotti and others for their help, encouragement and/or constructive feedback. Any remaining errors in methodology or results are my responsibility of course!!! If you want to provide constructive feedback, let me know.
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Major content related changes: November 18, 2023