On Earth, the Sun's light spectrum is very flat throughout the visible spectrum, as I recall. This should help it look white as no color is favored. A simple test might be to compare a white sheet of paper under a flourescent lamp and one adjacent with sunlight on it at noon, midday and setting.
However, the Sun's spectrum is not flat outside our atmosphere and it favors green and blue.
I have googled myself half silly trying to find information related to the eye's color cone's limits. The Sun may look white, as astronauts have said, because the flux has saturated the cones. I'd really like to know what the real color of the sun is, assuming I'm right. You would think someone by now would have either seen it through Cassini or another "true color" satellite or duplicated the Sun's real spectrum in a lab (at an unsaturated intensity level). I suppose asking for a satelite view of the sun would be like asking someone to take a sip of water from a fire hydrant.
I did find one site which gave the color cone's lower limit which equates to being able to see the color of the sun as far away as about 3500 AU. The rods take over and white is all you get.
Shucks...What Color is The Sun!!! ](*,)