The visit number is a three character number that indentifies the visit within an observation. Multiple visits per observation are needed for mosaics and some long observations. Note fields that trace back to the proposal are called numbers rather than IDs to emphasize that only decimal numbers can be used. The visit number can be found in both the visit, program and observation IDs.
| Attribute | Value |
|---|---|
| data type | string |
| enumerated Values | not defined |
| units | |
| example | 009 |
| default value | |
| special processing | not defined |
| source | Science Image Header |
| software source | |
| calculation | OBS_ID[10-12] |
| DB destination | ['ScienceCommon.visit', 'GuideStar.visit'] |
| data type in DB | smallint |
| instrument | Multiple |
| mode | All |
| product level | 1a |
| FITS hdu | PRIMARY |
| FITS header section | Observation identifiers |