NGAO Alignment, Calibration, and Diagnostics mini-review

Questions and comments from Jim Lyke

KAON 719

Sec. 2.4 Alignment Requirements

• Focal plane alignment (x,y), 4th bullet: Does DAVINCI team know about instrument position requirement to 0.2 mm or a possible alignable coronographic field stop and has it been designed?
• Pupil plane alignment (x,y), 1st bullet: Does DAVINCI team know about this 75 micron requirement?
• Tilt (theta x, theta y), 2nd bullet: Would these off-axis aberations add to the WF error budget? Is there a rough calculation?
• General question: Have requirements for xyz stage for the kinematic instrument mounts been fleshed out? If not, please consider discussing with DAVINCI team.
• LGS WFS to AO bench
  • Focal plane alignment (x,y), 2nd bullet: Is this in the f/15 beam? If so, <0.2 arcseconds is <0.14 mm, which seems tight. What is the range of the fast TT mirrors? If 5", seems this could be relaxed by a factor of 2 without losing much dynamic range and still be smaller than median seeing.
  • Focal plane alignment (z): 2 mm is not critical if and only if the LGS WFS focus stage is not near a limit or end of travel.
• Calibration Unit
  • Implies an on-axis point source at NGS focus, are there 3 off-axis point sources that can be fed into the LOWFS? Will these be available to use simultaneously with the LGS sources to simulate observing? This is a vital testing mode.
  • In addition to focus range to accomodate an ADC, phase retrieval (image sharpening) requires +/- 4 mm of defocus at f/15, psuedo pupil requires +/- 10 mm defocus @f/15
  • Is there a Na layer at 150 km? Can the 80 km conjugate track to 90 km?

Sec. 3.7 LOWFS to AO Relay Alignment

• Does aligning the LOWFS via the TWFS align all three LOWFS or just the one with the TWFS?

Sec 3.10 DAVINCI Science Instrument to AO Bench Alignment

• Do you expect DAVINCI to have xyz adjustments for its kinematic mounts?
• Why is there no pupil imaging mode for DAVINCI? It has proved very useful for K2AO

Sec 3.11 AO Bench Warm Enclosure Testing

• What is the mechanism to align both science instrument detectors and the coronographic focal plane mask?

Sec 4.2 Summit Alignment Preparations

• Who is responsible for deconstructing/decommissioning K2AO and NIRC2?
• What is the proposed schedule?
• What is the design load of K2 LNAS? How does it compare to the likely weight of the new AO enclosure, bench, and DAVINCI?
• Are the design mods to K2 LNAS envisioned to be major?