Starfield with White Background

Hi Everyone, I'm trying to create a starfield with a white background
similar to this one:
http://gallery.artofgregmartin.com/tuts_arts/making_a_star_field.html
(except this one has a black background).  I managed to get the stars
displaying nicely but I'm still having trouble creating the glow
effect.  If I use linear burn, the glow becomes unnatural (sharpish
around the edges and not very glowy).  I also tried playing around
with the colour balance and the edges of the glow seem to have
smoothed out a wee bit but still not enough.  Am I taking the wrong
approach to do this or does someone have a better way to accomplish
the effect?  Thanks!