P2.6 Tip-Tilt internal fast loop test with ASM turbulence

• Phase : 2
• Status : COMPLETE
• Category : Daytime testing (functionality and operability) (C3)
• Recurrence : after instrument installation at telescope platform
• Duration : 1 day

Description

• To verify the SHARK-NIR internal fast tip-tilt loop (using CRED2 and SHARK-NIR ALPAO DM) using the ARGOS light source (only at zenith) for various seeing conditions (0.5", 0.8" [or larger, if possible]) simulated at the ASM. This test will verify if the correction of the fast tip-tilt loop is affected by the residual turbulence for star at different magnitudes. In Padova just tip-tilt was injected and it was injected on the DM mirror used also for its correction.
• Before or after the previous test, we will also perform a short test (about 30 mins long) to find the center of the field while derotating.

Prerequisites

• Argos light source magnitude tuning or ND filters internal to SHARK-NIR will be used to test different magnitudes.
• For the SN team: know in advance how many minutes of data can be downloaded from CRED2 or the ring-buffer size. At least barycenter position should be saved, in a format compatible with statistical analyses.

Procedure for the Tip-Tilt internal fast loop test

• Use ARGOS light source (to be used only at zenith) and direct light towards SHARK-NIR.
• Close the SOUL AO loop to have the best ASM shape. Keep the ASM static with the best shape.

Test A1.

• Close the SHARK-NIR internal tip-tilt loop.
• Take 5mins of data at the CRED2 (at loop frame rate) and SCICAM.
• Introduce 0.5" seeing at the ASM and close the loop at 500 hz.
• Close the SHARK-NIR internal tip-tilt loop.

Test A2. Repeat test A1 with 1000Hz.

Test B1.

• Take 5mins of data at the CRED2 and SCICAM.
• Introduce 0.8" seeing at the ASM and close the loop.
• Close the SHARK-NIR internal tip-tilt loop.
• Take 5mins of data at the CRED2 and SCICAM.

Test B2. Repeat test A1 with 1000Hz.

Test C.

• Repeat the above steps of test B for the differentt selected brightness of the Argos light source (10th (max achievable), 12th, others TBC)

Procedure for finding the field center

• Use ARGOS light source (to be used only at zenith) and direct light towards SHARK-NIR.
• Close the SOUL AO loop to have the best ASM shape. Keep the ASM static with the best shape.
• Keep the SHARK-NIR internal tip-tilt loop OPEN.
• Move the derotator in 10 degrees (TBD) step and take an image at each position. From the data taken, estimate the center of the field.

Templates

Notes From Jenny: Setting the argos light source is set by adjusting the shutter. There is no document outlining the magnitude ranges. The brightest setting is about 10th mag and it can be adjusted down to 17.5 in varying increments. The wfs can tell us the approximate magnitude setting and allow us to tune. We know approximate settings for varying typical magnitudes from previous tests. We do expect to work on tuning the wfs Flux calibration to ensure the feed back on the wfs is accurate and we obtaining the optimal loop parameters for a given magnitude. The Flux on the wfs is translated to a magnitude.

Success criteria

• SHARK-NIR fast tip-tilt loop works efficiently within the requirements in all the seeing conditions and magnitudes (comparing open-close loop variation with different injected turbulence).
• The center of field estimated.

LBTO support

• Authorize SHARK-NIR
• Permission to use SX-ASM and LBTI-AO
• SOUL-LBTI AO support
• AO support
• SHARK-NIR TECCAM shall be connected to LBTO glycol lines

Date performed and by whom

• November 10th Luca, Daniele, Elena and remote support by Fulvio