NEBULAE
| Date | Clue |
|---|---|
| 2020-05-17 | Interstellar clouds |
| 2016-08-29 | Cosmic clouds |
| 2016-06-10 | Very distant clouds |
| 2013-12-09 | Interstellar clouds |
| 2013-02-24 | Parts of galaxies |
| 2012-05-28 | Interstellar clouds |
| 2007-12-02 | Space clouds |
| 2003-03-16 | Clouds of gas and dust |
| 1999-12-26 | Hubble telescope subjects |
| 1999-10-01 | Astronomers' subjects |
| 1998-10-31 | Parts of sky maps |