Pictures taken by astronauts on the moon always show the moon sky to be black.
There is no atmosphere on the Moon, so therefore nothing to scatter the sunlight. The key for the difference in color between the forward and side directions is that Rayleigh scatterers scatter blue light much more than red. The difference between the traveler and sailors is the amount of atmosphere that look through and thus the strength of the effect. The traveler looks through more atmosphere and sees the larger effect. The pollutants Rayleigh scatter light just like the pure atmosphere.