== P3.15 Astrometry plate scale and orientation == • **Phase** : 3 • **Status** : Draft • **Category** : Nighttime Science Calibration (C5) • **Recurrence** : every night starting from commissioning • **Duration** : 1 hour **Description** • Determine the astrometry of the science frame. Deduce detector on sky coordinates & plate scale from RA & DEC of a known multiple stellar systems. This calibration is to be done for a reference setup. **Prerequisites** • Authorize SHARK-NIR on the SX side. • Atmospheric conditions: AO working conditions. • Bad pixel map, Background or Dark, Flat-field, distortion map **Procedure** • Observe multiple system(s) with known characteristics without the coronagraph **Success criteria** • Image scale better than 5 mas (goal 0.5 mas) over FoV, image orientation better than 3 arcmin (goal 18 arcsec) **Notes** • Same as activity 7.1 in AD4 **LBTO support** • SOUL-AO support **Associated SHARK-NIR personnel** **Date performed and by whom**