Still learning, thinking - and failing - about the moon.
timeanddate.com has this cute and dynamic moon sketch at e.g. https://www.timeanddate.com/moon/uk/london
They generate this based on three parameters that they call
r. The above image is the result of invoking this: https://www.timeanddate.com/scripts/moon.php?i=0.028&p=3.388&r=0.035.
I know that
i stands for i llumination in the range 0-1.
However, what are
r and in what unit? What are the likely correct terms?
r appears to be some sort of "rotation angle" of the moon while
p is the same for the "mask".