The Moons orbit is tilted at 5°8' to the ecliptic.
What is the lowest latitude from which the Moon may never set (the Moons arctic circle)?
The maximum height of the
ecliptic above the equator
is ε = +23°24'.
The Moon can get 5°8' above this, i.e. up to +28°32'.
So the Moon's maximum declination is +28°32'.
An object of declination δ
will be circumpolar
at latitude 90°-δ,
i.e. at latitude 61°28'.
So if the Moon is at its
greatest possible declination,
it appears circumpolar from any latitude north of 61°28'N.
(The northern tip of Shetland is at latitude 60°52'.)
Would the Moon always be circumpolar, at this latitude?
No; only at a major standstill.
Sometimes the Moons orbit
will be inclined the other way to the ecliptic,
and it will reach a maximum height of only 23°24' - 5°8' = 18°16'.
This is a minor standstill.
(The interval between major
standstills is 18.6 years.
Back to "ecliptic coordinates".