== P3.19	 Sky background == 
•	**Phase**		:	3  
•	**Status**		: 	Draft	 
•	**Category**		: 	Nighttime testing (functionality and operability) (C4)
•	**Recurrence**	: 	once at commissioning and then on request.
•	**Duration**		: 	10 minutes
**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**
•	Support from LBTI/LBTO?
**Associated SHARK-NIR personnel**
•	JF, LM, MdP
**Date performed and by whom**