== P3.18	Large spatial scale instrument and telescope flat field == 
•	**Phase**		:	3  
•	**Status**		: 	Draft	 
•	**Category**		: 	Nighttime testing (functionality and operability) (C4)
•	**Recurrence**	: 	before every night observations (valid for all observing	modes). 2/day for CI (BB filter only).
•	**Duration**		: 	1 hour(s)
**Description**
•	Flat field taken during twilight 
**Prerequisites**
•	Authorize SHARK-NIR on the SX side.
•	Atmospheric conditions: AO working conditions.
•	Bad pixel map, Background or Dark. 
**Procedure**
•	This calibration is performed by sky observation combined with pointing scan in order to record a flat (that include telescope large scale transmission variations) on the detector. 
•	Single integration times for a given setup, using various flux level with natural light with no coronagraph.
**Success criteria**
•	Width of flux distribution: 3.10-2  
**Notes**
•	Same as activity 7.5 in AD4
**LBTO support**
•	Support from LBTI/LBTO?
**Associated SHARK-NIR personnel**
•	JF, LM, MdP
**Date performed and by whom**