== P3.14 Sky background == • **Phase** : 3 • **Status** : Draft • **Category** : Nighttime testing (functionality and operability) (C5) + Nighttime calibration (C6) • **Recurrence** : once at commissioning and then on request. • **Duration** : 2 hours **Description** • Acquire a series of sky backgrounds from science images, expected mainly when observing extended objects. A short sky background may also be useful for remaining deviant pixel removal. **Prerequisites** • Authorize SHARK-NIR on the SX side. • Atmospheric conditions: AO working conditions??? **Procedure** • Observe a blank field close to the science target (separation~10-20 arcsec) • The same set-up as normal science observations but AO is not running and coronagraph may be removed. A list of telescope offsets is added to reach an “empty” field and jitter. **Success criteria** • 10% accuracy (dependent on measurement frequency) **Notes** • Same as activity 7.6 in AD4 **LBTO support** • SOUL-AO support **Associated SHARK-NIR personnel** **Date performed and by whom**