You can, but note that TOD_Sky.SunriseTime and TOD_Sky.SunsetTime don't influence the visuals of the sky you see at all - they are just values that are calculated from the current sun altitude - i.e. sunrise time is when the sun reaches an altitude greater than -6 in the morning and sunset time is when the sun reaches an altitude of -6 in the evening. The only things those values affect are the TOD_Time.OnSunrise and TOD_Time.OnSunset events, which in turn don't do anything unless you actually subscribed methods to them. I don't think that's the problem you're having, is it? I compared the sun altitude of Time of Day (TOD_Sky.SunAltitude) to the values you posted for London (on 2015-07-17) and they do match for sunset, sunrise, noon and midnight (with UTC+1). This confirms my suspicion that the sun position is calculated correctly. That being said, the visuals of the sky - i.e. the light scattering a given sun altitude results in - can still be different than those in London of course, which I cannot confirm without seeing the real deal. This could be caused by the atmospheric parameters not matching those in London or an inaccurate or faulty calculation somewhere. It's difficult for me to check that without having comparison shots. I might be able to get some high quality photographs for various times around sunset and sunrise where I live, but that's quite a bit further south than London. There's of course also the option for me to simply add an artistic scattering multiplier for sun altitudes below 0, which would allow you to artificially darken the sky sooner or later.