Hi Don,

I cant calculate that for you at the moment (its not in mathematica), I would have to learn the theory to generate it, and I dont have the time for that.

However, your value is most likely correct for the refractive index, and wont change appreciatively from that value. That value though is for yellow light (specifically 589.8 nm AKA Sodium D emission). Typically for the visible portion and near UV and IR) the refractive index decreases with increasing wavelength. What this means is that for 700 nm, on mars (or any planet), your value of 1.30055 is the upper limit. Whats more pressure effects the refractive index of gases, and the lower the atmospheric pressure, the closer the refractive index will approach the vacuum value of exactly 1. Again this indicates that the value of 1.30055 will be the upper limit.

Jonny