When viewing clusters of Stars which are at a large distance from the origin, e.g. in the LMC, often large translucent blotches are drawn, overlaying the stars in front of the viewpoint. The translucent blotches look like they might images of stars which are slightly behind the viewpoint.
This problem is seen in Celestia v1.6.0 and in r5147
The attached zip file includes such a cluster of stars with a URL to illustrate the problem.
mis-drawn stars addon