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

• Phase : 2
• Status : Draft
• 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

• Knowledge of Argos light source magnitude and the possibility of tuning its brightness (more info pending from LBTO, jenny?). In alternative we can change magnitude with our ND filters.
• 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. Confirm if 10 mins are ok.

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 10mins of data at the CRED2 (at loop frame rate) and SCICAM at 500 Hz.
• 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 10mins 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 10mins 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 differnet selected brightness of the Argos light source (TBC which magnitudes, noting that max brightness should be mag 9th in R band)

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

Success criteria

• SHARK-NIR fast tip-tilt loop works efficiently within the requirements in all the seeing conditions and magnitudes (comparison between 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

Date performed and by whom November 10th Luca, Daniele, Elena and remote support by Fulvio