| name | type | length | unit | ucd | description |
| maskID | bigint | 8 | | ID_CATALOG | Unique Id number, composed of skyversion, rerun, run, camcol, field, filter, mask |
| run | smallint | 2 | | OBS_RUN | Run number |
| rerun | smallint | 2 | | CODE_MISC | Rerun number |
| camcol | tinyint | 1 | | INST_ID | Camera column |
| field | smallint | 2 | | ID_FIELD | Field number |
| mask | smallint | 2 | | ID_NUMBER | The object id within a field. Usually changes between reruns of the same field. |
| filter | tinyint | 1 | | INST_ID | The enumerated filter [0..4] |
| ra | float | 8 | deg | POS_EQ_RA_MAIN | J2000 right ascension (r') |
| dec | float | 8 | deg | POS_EQ_DEC_MAIN | J2000 declination (r') |
| radius | float | 8 | deg | EXTENSION_RAD | the radius of the bounding circle |
| area | varchar | 4096 | | EXTENSION | Area descriptor for the mask object |
type | int | 4 | | CLASS_CODE | enumerated type of mask |
| seeing | real | 4 | arcsecs | INST_SEEING | seeing width |
| cx | float | 8 | | POS_EQ_CART_X | unit vector for ra+dec |
| cy | float | 8 | | POS_EQ_CART_y | unit vector for ra+dec |
| cz | float | 8 | | POS_EQ_CART_Z | unit vector for ra+dec |
| htmID | bigint | 8 | | CODE_HTM | 20-deep hierarchical trangular mesh ID of this object |