P3.14 Star center Fourier mode images

• Phase : 3
• Status : COMPLETE, checks at fainter magnitude stars to be performed later with low priority
• Category : Nighttime testing (functionality and operability) (C5) + Nighttime calibration (C6)
• Recurrence : once after instrument installation at telescope platform
• Duration : 1 hour

Description

• This calibration is performed to calibrate the target star center 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 corresponding image's required specifications 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.

Templates

• There is no template as of now (12 Oct 2023). The Fourier modes are injected by the LBT ASM experts [Guido and Xang-yu]. Currently, they are working to make the procedure automated.

Success criteria

• Accuracy of 3 mas (goal 1 mas)
• A report of the activity performed during daytime tests on 15, 20, and 21 of December 2022 using SHARK-NIR coupled with the M2 adaptive secondary mirror (ASM) of LBT can be found in this ​link
• Details of the activity done on-sky and a summary can be found in the minutes of the run.

Notes

• Same as activity 7.8 in AD4

LBTO support

• AO support

Date performed and by whom