This is what I wrote for my project on this exact question! Hope this helps!
Now, Jane and John are in a different situation, observing stars through a telescope. The Doppler effect is also true for light emitted by stars, but instead of hearing the difference, you see the difference in their color. You know if a star is coming or going from the color it emits. Based on how close and in what direction the star is moving, the star can look very different. One person could be looking at a star and see a red color light being emmited from the star. This basically means the star is traveling in the direction of the person viewing it. This person could also see another star and see a blue color light being emmited from the star. This simply means the star in traveling away from the person viewing it.
Also, of course the size could be different based on how close the star is. We know all stars are extremely far away from earth but you can tell if a star is closer to earth than another star based on if it is relatively larger than than other star and if it is brighter. To John, the star he sees has a blue light so his star is traveling away from him. However, to Jane her star has a red light which means that star is traveling towards the earth. To summarize, Jane's star has a red light and is traveling towards the earth while John's star star has a blue light and is traveling away from the earth. This is also a prime example of the Doppler Effect in motion. The stars look different because they are traveling in different directions.
