PSF Reconstruction Resource Page

---

The characterization of the PSF over the focal plane of the Science Instrument is critical to the AO astronomy community. The W. M. Keck Observatory (WMKO) submitted a 2-year proposal to CfAO (P.I. D. Le Mignant; AO Researcher: R. Flicker) for a telemetry-based PSF reconstruction project. CfAO has previously funded various PSF characterization projects that have led to significant progress in this field.

This TWiki page is the main resource page for the WMKO PSF Reconstruction project as well as a resource page for past and current AO PSF reconstruction efforts. If you are working in the field of PSF reconstruction, we encourage you to register and edit a section in this page.

---

1. PSF Reconstruction at WMKO

• PSF Reconstruction Proposal (PDF) submitted to CfAO for their Y9 funding. The proposal was accepted in July 2007 and started in November 2007.
• April 08: Y9 report to the CfAO for the proposal period November 2007 - April 2008, written by Ralf and David. This report is joined to a request for funding in Y10 (Nov. 08 till Nov. 09), at the same level, along the lines described in our original proposal.
• June 08: Report from the reviewer on our Y9 progress report.
• July 08: Got the funding for Y10 (Nov. 08 till Nov. 09) ! Our proposal was evaluated at 4.2/5.
• September 08: PSF reconstruction poster presented at the Keck Science Meeting (PPT)
• October 08: Phase 1 final report (PDF, PS).

The proposal outlines three major phases of the project, described in roughly chronological order as:

• Phase 1: Initial development, on-axis NGS only (8 months)
  • Review previous research on PSF reconstruction and select candidate algorithms
  • Develop K2 AO simulation tools for the purpose of producing simulated AO telemetry data
  • Develop TRS (telemetry recorder/server) query and analysis tools
  • Develop prototype PSF reconstruction algorithm containing the fundamental components (fitting, aliasing, noise and bandwidth errors); test on simulated data and apply to real on-axis NGS K2 AO data
• Phase 2: On-sky validation and component development, off-axis NGS, LGS, optical aberrations (12 months)
  • Develop and validate angular and focal anisoplanatism components for NGS and LGS
  • Develop static and dynamic telescope aberration components (segment figures, vibrations, instrument optical distortions); strategy for measuring them
  • Integrated product development, preliminary deployment to routine observing
• Phase 3: Final product and future development (4 months)
  • Integrated product and user interface development
  • Initial studies into PSF reconstruction techniques for future multi-beacon tomographic AO systems (i.e. MCAO, MOAO, LTAO) and extremely-high-order AO systems (applicable to, e.g., NGAO)

Phase 1: Component Modeling and Analysis

PSF reconstruction working notes (2008-04-25) - this is a technical document containing aspects of mathematical modeling, analysis and simulations. Individual sections on component modeling can be accessed in the table below:

Phase 1 final report (PDF, PS). This is the final version of the technical draft linked above.

Codes and numerical computation

The IDL codes written for the PSF reconstruction are available upon request. Section 7 "Numerical Computation" in the Phase 1 report contains a brief description of the current set of codes and some instructions on how to use them. One reason why we do not simply make them available here is that some of it is specific to Keck and relies on certain directory structures and pre-compiled non-standard IDL packages. Anyone interested in the codes are asked to contact Chris Neyman at WMKO (cneyman_at_keck.hawaii.edu).

K2AO Engineering Data:

The purpose of this table is to keep a log of the data collected in support of the project. Also, this may be useful for future projects (the observation logs are given in the appendix of the Phase 1 Final Report).

Purpose	Type	Date	Remarks
Noise model validation	NIRC2, WFC data on simulation source	2007-12-10	2h - Collected data for range of frame rate, SNR and gains
r0 Estimation	NIRC2, ACAM and WFC open and closed loops on bright stars	2008-01-14	3h - Good conditions
NGS bright star, on-axis reconstruction	NIRC2, ACAM, and WFC (see night summary)	2008-04-22	2h - Bad conditions
Noise model validation	NIRC2, WFC data on simulation source	2008-04-28	2h - Setup: 1kHz, 70cts/subap, 1% SND, Br gamma - Investigated range of DTT, DM and centroid gain and NIRC2 setup
Noise model validation	NIRC2, WFC data on simulation source	2008-05-06	2h - Same setup (+ Jcont and Hcont) - Sampled range of DTT, DM and centroid gain using automated script
NGS bright star, on-axis	NIRC2 and WFC	2008-07-17	3h - Bad seeing (1-2 arcsec) for most of time - 30 min of decent data with various values for gain centroid, DTT and DM gains
NGS bright star, on-axis+anisoplanatism	NIRC2 and WFC	2008-08-11	2h30 of good data - Bright and faint stars with variations of DM, DTT and centroid gains in narrow band H cont and Br gamma . Also, data on M15 with AO guide star R~ 12mag - all in NIRC2 narrow field
LGS bright star, on-axis+anisoplanatism??	NIRC2 and WFC	2008-09-16	3h allocated

2. PSF Reconstruction Meetings

• This brief overview presentation (PSFrec_cfao021107.pdf) was given at the 2007 CfAO fall retreat at Lake Arrowhead.

3. Links to PSF Reconstruction projects and published material

• The 2004 PSF Reconstruction Workshop included excellent presentations.

4. Contacts List

Name	Institution	e-mail
Chris Neyman	W. M. Keck Observatory	cneyman_at_keck.hawaii.edu
David Le Mignant	W. M. Keck Observatory	davidl_at_keck.hawaii.edu

Don Gavel	UC Santa Cruz	gavel_at_ucolick.org
Brent Ellerbroek	Thirty Meter Telescope	brente_at_caltech.edu
Jean-Pierre Véran	Herzberg Institute of Astrophysics	Jean-Pierre.Veran_at_nrc-cnrc.gc.ca