| # | Title | Status | Researcher | Start date | End date | Requested data types |
|---|---|---|---|---|---|---|
| 254 | Minor Outburst and Monitoring Requests of Variable Stars GK Persei, AN Ursae Majoris, and QR Andromedae | Archived | AAVSO | 1999-02-22 (UTC) | 1999-12-31 (UTC) | Photometry |
| 253 | Special and unique optical monitoring request - 1522+45 GRB 990123 | Archived | AAVSO | 1999-01-23 (UTC) | 1999-04-23 (UTC) | Photometry |
| 252 | 1749-31 Nova Scorpii 1998 [V1142 Sco] | Archived | AAVSO | 1998-10-21 (UTC) | 1998-10-23 (UTC) | Photometry |
| 251 | 1903-50 Supernova 1998dq in NGC 6754 AND Rare outburst of the TOAD-type cataclysmic variable 1626+21 V592 Herculis AND Fading of 1544+28A R Coronae Bo | Archived | AAVSO | 1998-08-28 (UTC) | 1998-11-19 (UTC) | Photometry |
| 250 | Alert Notice 250: 1726-19 Nova Ophiuchi 1998 [V2487 Oph] | Archived | AAVSO | 1998-06-15 (UTC) | 1998-06-18 (UTC) | Spectroscopy, Photometry |
| 249 | 1041+12 Supernova 1998bu in NGC 3368 (= M96) | Archived | AAVSO | 1998-05-09 (UTC) | 1998-06-01 (UTC) | Photometry |
| 248 | 1750+18 Supernova 1998bp in NGC 6495 | Archived | AAVSO | 1998-04-29 (UTC) | 1998-05-01 (UTC) | Spectroscopy, Photometry |
| 247 | 1224-22 Supernova 1998bn in NGC 4462 | Archived | AAVSO | 1998-04-17 (UTC) | 1998-04-28 (UTC) | Photometry |
| 246 | 1151+55 Supernova 1998aq in NGC 3982 | Archived | AAVSO | 1998-04-13 (UTC) | 1998-04-15 (UTC) | Photometry |
| 245 | 1815-27 Nova Sagittarii 1998 | Archived | AAVSO | 1998-03-23 (UTC) | 1998-11-23 (UTC) | Spectroscopy, Photometry |
