Hi Tom,

> Is there an easy way to display asteroids only within a range of
> magnitudes, say., 18-20?

For the faint end, you would go into Data Shown and set the limiting
magnitude for asteroids. You could then make this either "fixed" (i.e.,
going to mag 20 no matter how far you zoom in or out... this will lead
to a blur of asteroids at wide fields of view) or "auto" (i.e., fainter
ones show up as you zoom in, then vanish as you zoom out).

There's no similar limit for the bright end, though.

-- Bill