The basic idea is that stars on the galaxy map would look better if they core and halo were separate graphics, the halo being invisible while zoomed out for sharp crispness. EDIT: rejected: There's also the possibility of rotating the halo to make the star "twinkle" on mouseover or while selected. And random combination of star cores and star halos (of the same color of course) multiply the number of unique appearances possible with the same number of graphics.
In the example bellow the halo and core both [edit: start] at 5% of the graphics size. In each successive example the halo is enlarged more than the core, untill finally the core is at 100% of the graphic's size and the halo is at 200%. I think it looks good. For economy the programmer might consider not even displaying the halo graphics at the lowest magnifications.

The largest size in my example is probably unnecessary, and ultimately the core star graphics could probably be shrunk to 64x64, but things can be easily shrunk later.
You can download the yellow test images from here. I think they will work better than breadman's test images because the halos have more transparency, and thus the "beams" will show through better.