P3.12 Star center Fourier mode images

• Phase : 3
• Status : Draft
• Category : Nighttime calibration (C5)
• Recurrence : on every target, starting from commissioning.
• Duration : 1 hour

Description

• This calibration is performed to calibrate the target star center with respect to the detector in order to provide a reference input for frame derotation and quadrant combination.

Prerequisites

• Authorize SHARK-NIR on the SX side.
• Atmospheric conditions: AO working conditions.
• Bad pixel map, Dark

Procedure

• DM produce a pattern offset with four spots symmetric with respect to the star + AO closed-loop + coronagraph
• The required specifications of the corresponding image are a grid of at least 2x2 regularly spaced focal plane image peaks within 5 and 15 lambda/D with FWHM < 45 mas and separation precision < 6 mas.
• DM offset applied on target acquisition to produce a waffle image. Find the center of the four first-order diffraction peaks (cross geometry) to deduce the pixel corresponding to the center field.

Success criteria

• Accuracy of 3 mas (goal 1 mas)

Notes

• Same as activity 7.8 in AD4

LBTO support

• SOUL-AO support

Associated SHARK-NIR personnel

Date performed and by whom

Comments

KR, EC, DV: confirm if we need this only for shaped-pupil or for all the coronagraphs? DV: New reference document coming up (will be added as an AD#)