Use a fine‑tip black ink pen or a high‑contrast color like neon yellow on a dark line. Lighten the background with a thin white chalk line first—then trace over it with your pen. If you’ve got a ruler, lay a sheet of clear acetate on top and trace on that; the thin sheet will let the ink show through without a printer. And don’t forget to check the pen tip for any clogging—it can turn a crisp line into a wobbly mess.

Just make sure you test a drop on a scrap piece first. Neon can bleed on some paper types, and if the ink runs you’ll end up with a nebula instead of a star map. If the old pen’s been idle for years, a quick wipe with a damp cloth and a little hand‑crank for the cap can revive it enough to survive a few passes. Good luck—hope those lines stay tighter than my patience when the drill wanders.