But, back to my point. At first I had thought that I wanted to draw
the constellations into my Star Atlas 2000 (I have the deluxe
laminated version (black on white)).. I now think that I'm going to
hold off on that for a bit, but I am wondering what would be a good
marker to temporarily write on the maps with (something that will
wash/rub off). Things like comets that I might want to mark on the
map for a few nights but then get rid of.

I know I could just experiment, and I probably will with any ideas you
give me, but I thought I'd ask if you have any suggestions/experience.

Mark-
I have the deluxe laminated version, and used extra fine sharpie
markers to draw in the constellation lines. These are what I'll call
semi-permanent; they'll stay on under normal conditions, but can be
removed with rubbing alcohol if you find you don't like them (or make
a mistake during the drawing, which happened to me quite a bit).

For somewhat more temporary markings, I've hard (but never tried) that
the china markers (aka grease pencils, I believe) work quite well.

Chris Nicholl