| Dr P Hakala | (Finland) | 14/9/99 - 6/10/99 |
| Prof B Johnson | (Newcastle upon Tyne) | 15/12/99 - 18/12/99 |
| Prof O H Kegel | (Freiburg) | 22/9/99 - 22/10/99 |
| Prof L Mestel | (Sussex) | 22/9/99 - 14/10/99 |
| Prof D Mihalas | (Los Alamos Lab.) | 27/9/99 - 4/10/99 |
| Dr G Parmeggiani | (Universita degli Studi di Padova) | 12/7/99 - 13/8/99 |
| Dr E Regos | (Cambridge) | 13/7/99 - 29/7/99 |
| Dr C Tout | (Cambridge) | 13/7/99 - 29/7/99 |
| Prof B Warner | (Cape Town) | 1/7/99 - 9/7/99 |
| Prof R Webbink | (Illinois at Urbana) | 13/6/99 - 23/7/99 |