Pyramid sensors for AO and co-phasing. Two key projects in Arcetri AO groups for 8m class telescopes and ELT wavefront sensing: -WFS for LBT AO system -Segment co-phasing for EELT. PS. SH. Pyramid WFS in Adaptive Optics.
Pyramid sensors for AO and co-phasing
Two key projects in Arcetri AO groups for 8m class telescopes and ELT wavefront sensing:
-WFS for LBT AO system
-Segment co-phasing for EELT
A Strehl Ratio plot (peak value of the corrected PSF normalized to peak value for perfect correction) as a function of guide star magnitude in R band for Pyramid Sensor (PS) and Shack-Hartmann sensor (SH).
PS is less sensitive to uncorrected
atmospheric perturbations. Energy
left In the PSF halo is 1/3 for PS.
Enabling higher PSF contrast.
PS achieve same performance
With a star about 2 mag fainter.
AO system sky coverage is
Strehl Ratio in seeing
limited case (8m tel.)
FLAO on LBT telescope
The secondary unit
The pyramid WFS unit
Acquisition & guiding AG unit
Wavefront sensing W unit
The WFS board during integration
The glass pyramid
for LBT WFS
The lab set-up for AO system test
The 45 actuators prototype
of deformable secondary
Arcetri AO group demonstrated that the Pyramid sensor can detect simultaneously
segment differential piston as well as tip and tilt of the segments.
-A single WFS for segmented mirror alignment
-A single WFS for co-phasing and AO
Closed loop alignment
of the segmented DM
of NAOMI AO system @ WHT
Piston signals, (X,Y)
Tip tilt rms
Tilt signals (X,Y)
The active Phasing Experiment (APE)
Active Phasing Experiment (APE) is the WP4600
of the ELT Design Study. Experiment is aimed to
realize , test and compare three co-phasing
Sensor in lab at ESO and at the VLT.
Initial rms > λ/2
Start 110nm rms
Stop 12nm rms
Final rms 23nm
LGS GLAO system for LBT
A project to provide LBT with a Laser Guide Star Ground Layer AO system is started as phase A study in May07. The program has an upgrade path aimed to extend GLAO system to LGS diffraction limited AO for imaging on small FoV.
-GLAO system will be coupled with the multi-object spectroscopic unit of LUCIFER having a 4x2 arcmin FoV.
MCAO for EELT phase A study
A 2 years phase A study to analize
the design of a Multi-Conjugate AO
system for the EELT leaded by
Osservatorio di Bologna (OAB).