Translation for "equinox"

Mae govannen! I am translating a poem in both Quenya and Sindarin right now and need a word for equinox. I took the primitive roots √IM, √DŌMĒ, and √MOR(I), because "equinox" literally means "equal/same night".

For Sindarin, I have imdú or imor:

im-dōmē > imdōme > imdūme > imdūm > imdūv > imdū

im-mori > immore > immor > imor

For Quenya, I have immórë.

Do these work?

I am not sure about imdu Primitive Elvish here shows [md] > [nd].

That is how we get hond. So I think this would be innu.

Annon allen!

Liston allen! "I show grace to you!"

Not sure it that works for "You are welcome" but I am going to roll with it.