Blockquote[quote=“Jason_Goff, post:6, topic:2657”]
That would depend on the size of the moons, their proximity to Athas, and Athas’ proximity to the Red Giant. Another factor to consider is phases, if the moons move very quickly around Athas there would be few phases. I haven’t studied the Cosmos around Athas enough in depth to answer that.
I have studied this. A lot. I have spent days plugging the calculations in for different orbital periods for the moons along with varying distances, sizes, and masses all to make it work according to how real physics works.
I think Athas isn’t too different than Earth size wise. The mass is about the same. Other wise gravity would operate differently. (All rules treat gravity as normal)
Distance from the sun is a little more giving 375 day orbit vice 365.25.
Moons have to have orbital periods that result in an eclipse every 11 years. Or 4125 days. I’m am in agreement with Agantyr the maker of the Merchant Calendar program. (Find this in the athas site.) he uses 125 for Guthay and 33 for Ral.). Though other combinations could work. I think 125 and 33 work best.
If you are interested in the moons of Athas check out my info here:
There isn’t a way under physics that I am aware of would allow one of the moons to be causing the night. Day/night is the planet simply rotating on its axis. Moons do cause eclipses.
The major one mentioned in the rule book happens at the first day of the year which is also at High Sun, the summer solstice. This eclipse is really a conjunction of Ral passing in front of Guthay when they are both full. So they are on the opposite side of the planet from the sun. I would assume they also pass thru Athas shadow as well turning them red color.
But what is often overlooked is the other eclipse that also happens every 11 years, but 5.5 years later at Low Sun when both moon are new and cross the face of the sun.
Depending in the apparent size of the moons and sun this may look like two black circles crossing the sun blocking light partially. Or blocking it completely like a regular solar eclipse.
I highly recommend you download the merchant calendar program and play around with it.
My two ceramic pieces.