== P3.17	Atmospheric calibration and absolute flux calibration == 
•	**Phase**		:	3  
•	**Status**		: 	Draft	 
•	**Category**		: 	Nighttime testing (functionality and operability) (C4)
•	**Recurrence**	: 	once at commissioning and then for each LSS observation observations.
•	**Duration**		: 	20 minutes
**Description**
•	Atmospheric calibration to remove telluric atmospheric features from the stellar spectrum and get absolute flux calibration per spectral resolution element. 
**Prerequisites**
•	Authorize SHARK-NIR on the SX side.
•	Atmospheric conditions: AO working conditions.
•	Bad pixel map, Background or Dark, Flat-field, wavelength calibration. 
**Procedure**
•	Observe the spectrum of a featureless (and/or standard) star at similar airmass that of the science target.
**Success criteria**
•	Better than 10% for absolute flux calibration and for average residuals from telluric removal.
**Notes**
•	Same as activity 7.4 in AD4
**LBTO support**
•	Support from LBTI/LBTO?
**Associated SHARK-NIR personnel**
•	JF, LM, MdP
**Date performed and by whom**