Recently, I have been workimg calculating the internal radiance fields for an entry probe dropping into the atmosphere of a planet. This entailed implementing some additional code within NEMESIS and also considerable post-processing of the output.
We presented our work at the EPSC 2020 meeting, and copies of the presentations may be found here for Uranus and for Venus.
In addition, I wanted to see what the atmospheres of Uranus and Venus would look like for a human observer who happened to 'hitch' a ride with the probes. While I was doing this, I realised that I would be able to similate what the whole 3-dimensional planets would look like on approach and decided to simulate this as well. Even though I use a plane-parallel multiple-scattering code, I was able to achieve this by making the assumption that locally the atmosphere was plane parallel and combine multiple simulations with the sun at different zenith angles. These simulations were then combined into movies that we uploaded to YouTube and which are available either from the Oxford Physics news link or directly from YouTube for Uranus and for Venus.
Pay close attention to the Venus simulation - in the approach phase you can see a scattering effect called the 'glory' when the sun is directly behind you. This has actually been seen by Venus orbiters and came out of these simulations without intentionally trying to recreate it, which was very satisfying. Also, as the probe nears the ground you'll be able to see surface features appearing out of the foggy gloom. In fact, in these simulations there is no fog or haze near the ground at all. The scattering you see is entirely due to the Rayleigh scattering of the air molecules. On Earth this gives us our nice blue sky. On Venus, where the surface pressure is 90 times that of Earth it gives rise to something that looks like haze!
Rayleigh scattering is also contributing to the blueness of Uranus's atmosphere, but here there is in addition the absorption of methane gas, which absorbs red colours, leaving the atmosphere looking particularly blue! Especially at depth!