LBT FLAO system: an attempt to highlight Piero’s views about the project.

Disclaimer: the opinions contained in the presentation are shared between most of the memebr of the AO group. However they sometime differs from the opinions of Piero !!!!

Talk summary

The FLAO system main components- The adaptive secondary mirror- The wavefront sensor

The system performance in solar tower & on sky

Possible FLAO upgrades for LBT & ELTs

The Principles of Piero-dynamics

1) Avoiding people get satisfied with what they have already found.

2) Convincing people they can do what they think is possible....and spending days of discussions convincing them.

3) Supporting the idea that lenghtly plans can be unnecessary.

4) Disappointing people changing idea when new technical reasons show a new (but barely possible) solution.

Applications of Piero-dynamics principles to the FLAO system development, realization and upgrades, as known to the Arcetri AO group, will be highlighted in red in this presentation.

A system Overview

LBT672a unit• 911mm diameter• 1.6mm thick, (Mirror lab)• 672 actuators• Settling time < 1ms• 30nm WFE

LBT WFS unit• Pyramid sensor• 30x30 to 5x5 subap.• Tilt mod. 2-6 l/D• 1Kfps max [30x30]

....as planned in 2001

The adaptive secondary mirror

Missing picture of P25 prototype.

The pros: no one even think in 2001 of realize such a complicate thing for a real telescope.Validation: a sentence from Guy Monnet, head of Instrumenation department at ESO ,(a very polite and competent person): «Simone, I do not think this is a good project for a post-doc . You should find something realizable»

The cons: it can not provide correction in the visible and/or can not achieve contrasts of 10^-7 easily. However upgrades are still possibles.......

The pyramid WFS

The pros: 1) other people consider the idea totally useless.

Tipically Italian. It sounds like buying a a shirt from Armani paying 1000 Euro for nothing.

2) Very easy to realize.

Notes from Arcetri AO meeting (2001): «Piero, we can not build it in 1 week!?!!» «Simone , be serious, we are speaking of a pyramid in front of a CCD......»

The cons: In the current project it uses only 30x30 subapertures and required at least 141 photons per mode to achieve SR of 80%. In H band. The target was 1 photon per mode.

System development schedule# of person involved (2001) => 8 # of years required => 3.5

Start date September 1°, 2001End date November 22°, 2004

Hmmm... too slow.

Do we really need this stuff ?!!

System performance at acceptance test.

Why only 78% in H band ?

Why stopping at mag 16.5 ? Still 30 photons per mode per frame.

Evaluation of system performance in the Arcetri AO group is not seen as particularly positive. Even if consistent with numerical results. A general important remark: why not going to visible wavelenght ?

The solar tower acceptance test took place in December 2009

Here, we have contrasting opionions between Masters:P. Salinari: «78% only, uhm...»R. Ragazzoni: «Simone, astronomer will blame us all for ages. Do not promise unachievable results»

FLAO system installation @ LBTFebruary 9th --March 17th .

FLAO system installation @ LBTFebruary 9th --March 17th .

FLAO system installation @ LBTFebruary 9th --March 17th .

FLAO system installation @ LBTFebruary 9th --March 17th .

FLAO system installation @ LBTFebruary 9th --March 17th .

FLAO system installation @ LBTFebruary 9th --March 17th .

FLAO system installation @ LBTFebruary 9th --March 17th .

First on sky results: May 25th

Intensities between open and closed loop rescaled for displaying purposes.

LBT InfraRed Test Camera images: H band, 10mas/pixel scale

The object:HD 124085, K0, R=7.5 , I=6.9, H=5.8, Triple StarThe atmosphere:seeing 0.6arcsec V band Elevation 58..64FLAO parameters:1 KHz, 30x30 subaps, 400 corrected modesResults: SR H 65%..73%

3.2 arcsec

Some of the first closed loop images acquired the 25th of May

From FLAO press release June 6, 2010.

The HD 124624 images and SRThe reference:HD 124624 [14:13:54.67 +37:37:34.2 ]R =7.1, H=4.4, J=5.1, K5III The atmosphere:seeing 0.9arcsec V bandFLAO parameters:1KHz, 30x30 subaps, 400 corrected modes

0.72”

H Band 75% SR in 12sec J Band 46.6% SR in 20 sec

Best SRs achieved!

85% H (1s)

47% J (1s)

High H band SR images

The reference: HD175658, R =6.5, H=2.5 The atmosphere: seeing 0.9 arcsec V bandFLAO parameters: 1KHz, 30x30 subaps, 400 corrected modes

First on sky results: a 40mas separation binary

Image dataH band 4s exposure time SR > 60% (no correction for 2nd star flux)

FLAO parameters30x30 subaps400 corrected modes1Khz frame rate

Star companion

Average value of closed loop time is 4h/night over 12 nights.

Each point correspond to a different target and reports an average value of the achieved SR.

H band SR vs star mag & seeing

Seeing values measured by LBT DIMM

K band SR values scaled from previous plot2MASS J19460752+2231122

R+I mag 17.0SR 6.2% H bandFWHM 0.1 arcsecDIMM 0.9”7x7 subaps36 modes, 200 Hz16 ph/subap/frame

2MASS J19334425+1947482R+I mag 17.8FWHM gain 1.4DIMM 0.9”7x7 subaps5 modes, 100Hz18 ph/subap/frame

Two on sky runs performed: May 25th-June 3rd, June 18th – June 25th

Some results from last run, 18-28 October

Seeing values between 1.0 and 1.8 arcsec. Performance shown in term of PSF difference between open loop and closed loop

Mag 12.5Peak’s ratio ~ 30FWHM DL

Mag 16.0Peaks ratio ~ 10FWHM < 0.1 arcsecMagnitude 16

Peak’s ratio ~ 10FWHM < 0.1 arcsec

Mag 17.5Peak’s ratio ~ 3FWHM TBD

93% SR (H band, 20sec. exposure)

HST WFPC3 H Band 20min

Imaging globular cluster NGC6341-M92

Dati sulla configurazione del sistema adattivo durante la osservazione

LBT test camera Limiting Magnitude H = 21, in 10minutes (with AO on)

The reference:R 11.5The atmosphere:seeing 0.7arcsec V bandElevation 58..69FLAO parameters:0.5KHz, 15x15 subaps, 153 corrected modes

FLAO H Band 8min

~10 arcsec

Composite image J+HComposite image J+H

However from Piero-Dynamics point of view we know that the most desired results is not been presented up to now.....

Sensor: E2V CCD47 Filter 850nm; BW 40nm

First on sky results: corrected image at 850nm

Star mag => R=9.3 J=7.5 H=6.7

Drizzling of 5 images SR~20% FWHM=40mas (DL=20mas)

IRTC H Band, scale=10mas/pix, SR~65%

Texp=6s, scale=20mas/pix

Horizontal cut

The 850nm SR is consistent with Marechal scaling of 65% SR in H band

From one Piero’s email:«E seguito a sopportare (pazientemente) . . .la mancanza dei promessi attachments!»«I keep waiting (patiently) for the missing promised attachments (of CCD47 images)»

The upgrade path: a first step with LLLCCDNow: about 70% SR with mag 13: sounds better!!

Finally a useful system: 10% SR in K band with mag 18.

.....It seems we are again on the right track: no one would believe a SR of 10% with an 18 magnitude star or 85% SR with magnitude 13.

Plot courtesy of M. Carbillet ( probably the next PI of FLAO development at LBT) and A. Riccardi (App. Opt, 2010)

A more sounding upgrade: add LGSs and a post focal corrector: MCAO correction in the visible

Pros: -people finally are convinced: the italians are crazy. -Easiness of realization-Need many actuators

Cons : no cons. -One warning: time scaling from previous FLAO system unpracticable (10 years for NGS, 40 years for LGS ?). Point to be revised.Baseline workaround: hire younger (cheaper) people for the team......

Change the already existing AGW unit (already proposed by ML Hart), and add a post focal deformable mirror conjugate to your favorite locations. Use multi-LGS to realize MCAO in the visible over FoV of 10/20 arcsec or more.

What’s next:E-ELTAlready good chances to place an adaptive secondary technology mirror on the EELT. This has been the critical step to divert LBT on a completely unforeseen path. Unfortunately people today are more suspicious......(8.4x5=42)

GMTThey have in the project adaptive secondaries and pyramid sensors. So here an upgrade is straightforward.

TMTSeem the more difficult to convince. However, who knows.......

One more Piero-Dynamics applications to ELT

ELT: of course here at least one important aspect has been neglected:

AO in the visible with 160000 actuators (on primary mirror segments)

Pros: Achieved angular resolution: 2.5 masDetectable magnitude (scaling from 8m telescopes): mag 33 in H band with 1h integration time & SNR=3

Cons: ??????

Acknowledgments:The Arcetri AO group wants to thanks Piero Salinari, the inventor of Piero-Dynamics, to make all this possible......... GRAZIE PIERO

FLAO system@ LBT: 85% SR (H band), Rmag=6.50seeing = 0.9