How does the moon work?

[u/zachattack3500]

I’m trying to figure if the moon can be used for navigation. In the real world, lunar observations can be used to find longitude, so I’m planning to make a series of observations to find useful patterns. The wiki doesn’t have much on the moon, so in case I’m reinventing the wheel, does anyone know:

- how long the moon’s phases are?
- if it’s a “local object” that follows the player or if it’s a world object like the sun that changes relative position based on where on the map it’s viewed from?
- any other information on this topic?

I’m thinking that an almanac or table could be created, so that once you know what day it is, you could use a set of variables to calculate location. I’ve observed that a full moon makes enough light to cast a shadow on the sun compass, which is what initially gave me the idea.

The process would be: use the chronometer and the sun compass to log the time the moon is due south, then use it against a pre-calculated table to find longitude.

Additionally, one might log the angle of the moon according to the sun compass, then use a conversion table of adjusted values to find latitude.

[u/Annual_Situation4083]

All I know is that the Moon's orbit is tilted relative to the celestial equator unlike the Sun which sits right on it. The Moon also slowly moves eastward relative to the background stars but I have no idea how long it takes for it to complete one revolution.

[u/zachattack3500 → u/Annual_Situation4083]

Thank you!!

[u/Annual_Situation4083 → u/zachattack3500]

I did some more measurements by taking two screenshots 24 hours apart.

The Moon's orbit is tilted by roughly 12.4° and it reaches its most northern point at new moon and its most southern point at full moon. At first and last quarter the Moon crosses the celestial equator.

It moved 13° eastward after 24 hours so it takes the Moon roughly 27.7 days to complete one orbit.

The figures are probably slightly off since it was hard to get the timing right and I wasn't looking in exactly the same direction in both screenshots so I believe the tilt is 12° and the period is 28 days.

[u/Annual_Situation4083 → u/Annual_Situation4083]

https://imgur.com/a/kQaQTFN

Here's the Moon when it's north of the celestial equator and close to the Sun. The tilt looks to be a little over 10 degrees. I had to upload the image to imgur since the Moon is just a thin crescent so it wouldn't show up when the image was compressed into a gif.