Certain stars are very distinctive. (All of this star-gazing works much better if you go out to a dark-sky area, and sit in the dark — no phone, no flashlight, nothing — and let your eyes adjust for at least a half hour.)
Betelgeuse in this photo is definitely red-orange to the naked eye. Just like seeing Mars and its reddish hue. Antares near the Milky Way core (not visible in winter) is bright red. The Orion Nebula is magenta that can be seen by the naked eye. Sirius in this photo is blue-white, but if you look around online you might find compilations of how different it can look depending on "seeing" conditions — how light is distorted and refracted in the atmosphere. Sirius, because it is the brightest star in the night sky, gets noticeably color-shifted by this effect sometimes.