P2.6 Measurement of NCPA

• Phase : 2
• Status : Draft
• Category : Daytime calibration (C3)
• Recurrence : after instrument installation at telescope platform
• Duration : 10 days

Description

• Measure the Non-Common Path Aberrations (NCPA).

Prerequisites

• Use of Argos swing arm / RR mounted on the SX side. SHARK-NIR aligned to telescope.

Procedure

• In closed-loop, we optimize the PSF shape on SCICAM using the trial & error algorithm used by the LBTO team during LUCI calibrations changing M2 reference shape applying modes coefficients (this is the baseline approach).
• We also perform the phase-diversity tests using the same light source and look at the NCPA output produced (in case the NCPA produced by the baseline approach is not stable enough for a longer period and/or if more correction seems necessary for high contrast).
• Depending on the two results and the quality of PSF, we may choose one or the other or the combination of both.
• There is also the NCPA test to be performed using the Wollaston prism + direct imaging in dual-band imaging mode. In the daytime, this may be performed using the ARGOS swing arm calibration unit light source (for zenith, and if required using RR on other elevation angles)
• Note that we may do this for different elevation angles.

Success criteria

• NCPA estimated and applied on the ASM (need to define a quantitative value?)
• Satisfactory PSF quality with closed-loop and get a new and improved daytime telescope model for SHARK-NIR?

Notes

• See activity 8.1 in AD4 for more details.

LBTO support

• Authorize SHARK-NIR on the SX side.
• Permission to use the Argos Swing Arm.
• When not using Argos swing arm and for different elevation angle tests, RR will be required on the SX side.
• Support from LBT SW Team, LBTI/Arcetri team to run SOUL AO

Associated SHARK-NIR personnel

Date performed and by whom