Figure with image mapped to spherical background

Hi, I am trying to make a 3-D plot which has a spherical background image. I have tried making a larger sphere that an image is mapped to, and then placing the other data to be plotted inside this sphere, and placing the camera inside the sphere. However when I do this the the figure displays as a circle, rather than the background image filling up the whole square area of the figure.

I have:

and my code is:

axis([-10 10 -10 10 -10 10])
[x,y,z]=sphere(50);
spherescale=10;
hold on
U_im=imread('esoMilkyway.jpg'); % Import texture data for Universe
Bg=surf((x*spherescale),(y*spherescale), (z*spherescale));
set(Bg,'facecolor','texturemap','cdata',U_im,'edgecolor','none');
daspect([1 1 1]);
campos([1 0 0]);
axis off    

The effect that I am trying to reproduce can be seen at 20:45 in this video: https://uk.mathworks.com/videos/modeling-and-simulation-with-matlab-a-case-study-in-problem-based-learning-90422.html

Also, when I rotate the figure the camera moves itself out of the sphere which is also something I would like to stop happening. If anyone can help me out that would be greatly appreciated.