| AAVSO | AstroWeb | AAS | Astro Meetings |
| ALMA Atacama Large Millimeter Array | Arcetri | ESO Garching | HST |
| IAU Home Page | IRAM Grenoble | ISO | |
| JCMT | KOSMA Univ. of Cologne | Leiden Observatory | INAF/IRA Bologna |
| MPIfR | NRAO | TNG-La Palma | SETI |
| STScI | VLA | ||
| SIMBAD | ADS Strassbourg mirror | NASA Photographic Database | |
| IPAC 2MASS,IRAS,ISO etc. | NED | NVSS | Skyview |
| Physical reference data | Physlink Physics & Astronomy reference | Useful info dip moms, freqs, coll. rate refs. | DSS-survey |
| IR lines atoms & molecules. | Lovas recommended rest freqs. | Molecular Spectrospcopy Homepage | Wordwide Molecular Ap. Resources |
| Astrophysical Calculator | Julian date converter | Conversion of units | ||
| Numerical Methods | StatCodes On-line statistical software | Coord. Conversion + Precession |