| Code | Category | Explanation |
|---|
| 1 | Note | One extremum per cycle. |
| 2 | Quality | Result based on less than full coverage, so that the period may be wrong by 30 percent or so. Also used to indicate cases where an ambiguity exists as to the number of extrema between lightcurves. Hence the result may be wrong by an integer ratio. |
| 3 | Note | Three extrema per cycle. |
| 4 | Quality | In addition to full coverage, denotes that a pole position is reported. |
| A | Note | Ambiguous period; the 'most likely' period is listed. |
| B | Note | Suspected binary on the basis of a secondary, non-commensurate periodicity in the lightcurve, indicating possible mutual eclipse phenomena. |
| D | Note | Rotation period 'determined' from published data, but not given by author(s) of original data. |
| N | Note | No lightcurve published. |
| P | Note | Photographic photometry. |
| R | Note | Radar. |
| T | Note | 'Tumbling' minor planet, that is non-principal axis rotation state. The dominant periodicity of the lightcurve is listed in the main table. The second period of the product harmonic function fitted to the lightcurve is listed in the end note, if it is determined. It is often not possible to determine which is a precession period and which is a rotation period. |
| V | Note | Visual photometry. |